Integer ambiguity search space reduction

ABSTRACT

A method of determining an integer ambiguity search space includes: obtaining, at an apparatus, a code phase measurement of a satellite vehicle signal comprising a pseudorandom noise code and a carrier signal; obtaining, at the apparatus, spatial information corresponding to a wireless terrestrial signal transferred between the apparatus and a terrestrial base station; determining, at the apparatus, a satellite positioning system carrier phase integer ambiguity search space based on the code phase measurement; and constraining a size of the satellite positioning system carrier phase integer ambiguity search space based on the spatial information.

BACKGROUND

Wireless communication systems have developed through variousgenerations, including a first-generation analog wireless phone service(1G), a second-generation (2G) digital wireless phone service (includinginterim 2.5G and 2.75G networks), a third-generation (3G) high speeddata, Internet-capable wireless service, a fourth-generation (4G)service (e.g., Long Term Evolution (LTE) or WiMax), a fifth-generation(5G) service, etc. There are presently many different types of wirelesscommunication systems in use, including Cellular and PersonalCommunications Service (PCS) systems. Examples of known cellular systemsinclude the cellular Analog Advanced Mobile Phone System (AMPS), anddigital cellular systems based on Code Division Multiple Access (CDMA),Frequency Division Multiple Access (FDMA), Orthogonal Frequency DivisionMultiple Access (OFDMA), Time Division Multiple Access (TDMA), theGlobal System for Mobile access (GSM) variation of TDMA, etc.

A fifth generation (5G) mobile standard calls for higher data transferspeeds, greater numbers of connections, and better coverage, among otherimprovements. The 5G standard, according to the Next Generation MobileNetworks Alliance, is designed to provide data rates of several tens ofmegabits per second to each of tens of thousands of users, with 1gigabit per second to tens of workers on an office floor. Severalhundreds of thousands of simultaneous connections should be supported inorder to support large sensor deployments. Consequently, the spectralefficiency of 5G mobile communications should be significantly enhancedcompared to the current 4G standard. Furthermore, signaling efficienciesshould be enhanced and latency should be substantially reduced comparedto current standards.

SUMMARY

In an embodiment, an apparatus includes: a receiver; a memory; and aprocessor communicatively coupled to the receiver and the memory andconfigured to: obtain a code phase measurement of a satellite vehiclesignal received via the receiver, the satellite vehicle signalcomprising a pseudorandom noise code and a carrier signal; obtainspatial information corresponding to a wireless terrestrial signaltransferred between the apparatus and a terrestrial base station; anddetermine a satellite positioning system carrier phase integer ambiguitysearch space based on the code phase measurement; where the processor isconfigured to constrain a size of the satellite positioning systemcarrier phase integer ambiguity search space based on the spatialinformation.

In an embodiment, a method of determining an integer ambiguity searchspace includes: obtaining, at an apparatus, a code phase measurement ofa satellite vehicle signal comprising a pseudorandom noise code and acarrier signal; obtaining, at the apparatus, spatial informationcorresponding to a wireless terrestrial signal transferred between theapparatus and a terrestrial base station; determining, at the apparatus,a satellite positioning system carrier phase integer ambiguity searchspace based on the code phase measurement; and constraining a size ofthe satellite positioning system carrier phase integer ambiguity searchspace based on the spatial information.

In an embodiment, an apparatus includes: means for obtaining a codephase measurement of a satellite vehicle signal comprising apseudorandom noise code and a carrier signal; means for obtainingspatial information corresponding to a wireless terrestrial signaltransferred between the apparatus and a terrestrial base station; meansfor determining a satellite positioning system carrier phase integerambiguity search space based on the code phase measurement; and meansfor constraining a size of the satellite positioning system carrierphase integer ambiguity search space based on the spatial information.

In an embodiment, a non-transitory, processor-readable storage mediumincludes processor-readable instructions to cause a processor, of anapparatus, to: obtain a code phase measurement of a satellite vehiclesignal comprising a pseudorandom noise code and a carrier signal; obtainspatial information corresponding to a wireless terrestrial signaltransferred between the apparatus and a terrestrial base station;determine a satellite positioning system carrier phase integer ambiguitysearch space based on the code phase measurement; and constrain a sizeof the satellite positioning system carrier phase integer ambiguitysearch space based on the spatial information.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a simplified diagram of an example wireless communicationssystem.

FIG. 2 is a block diagram of components of an example user equipmentshown in FIG. 1 .

FIG. 3 is a block diagram of components of an exampletransmission/reception point.

FIG. 4 is a block diagram of components of an example server, variousembodiments of which are shown in FIG. 1 .

FIG. 5 is a simplified diagram of an example user equipment.

FIG. 6 is a timing diagram of a carrier wave signal and a code phasemodulation signal included in a satellite vehicle signal.

FIG. 7 is a simplified view of the carrier signal shown in FIG. 6transmitted from a satellite to a receiver.

FIG. 8 is a simplified diagram of a carrier signal phase integerambiguity and integer ambiguity search space.

FIG. 9 is a simplified diagram of use of a range and range uncertaintyto reduce an integer ambiguity search space.

FIG. 10 is a simplified diagram of use of an angle and angle uncertaintyto reduce an integer ambiguity search space.

FIG. 11 is a simplified diagram of use of a position estimate andposition estimate uncertainty to reduce an integer ambiguity searchspace.

FIG. 12 is a simplified diagram of use of a combination of range andrange uncertainty, and an angle and angle uncertainty to reduce aninteger ambiguity search space.

FIG. 13 is a simplified diagram of use of a combination of multipleranges and corresponding range uncertainties, and an angle and angleuncertainty to reduce an integer ambiguity search space.

FIG. 14 is a signaling and process flow diagram for measuring carrierphase, and determining position information based on carrier phasemeasurements.

FIG. 15 is a block flow diagram of a method of determining an integerambiguity search space.

DETAILED DESCRIPTION

Techniques are discussed herein for reducing an integer ambiguity searchspace for determining a total carrier phase of a satellite signalbetween a satellite and a receiver. Spatial information determined fromone or more terrestrial-based signals may be used to determine a spatialconstraint on a location of a receiver. The spatial constraint is usedto bound an integer ambiguity search space for determining an integernumber of cycles of a carrier signal of a satellite signal between thesatellite and the receiver. For example, an error ellipse (or othershape, e.g., an irregular shape) corresponding to the search space maybe bound by a position estimate of the receiver relative to aterrestrial base station and an uncertainty of the position estimate. Asanother example, the error ellipse may be bound by a range from aterrestrial base station to the receiver and an uncertainty of therange. As another example, the error ellipse may be bound by an angle ofthe receiver relative to a terrestrial base station and an uncertaintyof the angle. As another example, combinations of multiple spatialconstraints may be used, e.g., multiple range constraints, multipleangle constraints, a position estimate and one or more angle constraintsand/or or one or more range constraints, one or more range constraintsand one or more angle constraints, etc. Other configurations, however,may be used.

Items and/or techniques described herein may provide one or more of thefollowing capabilities, as well as other capabilities not mentioned.High-accuracy positioning may be achieved using terrestrial-basedpositioning reference signals in combination with satellite positioningsignals. Carrier phase ambiguity resolution for high-precisionpositioning may be achieved faster, especially in non-open-skyenvironments. High-precision satellite-signal measurements may beachieved in environments in which such measurements previously could notbe achieved. Satellite positioning signal acquisition speed and/orsensitivity may be improved. Other capabilities may be provided and notevery implementation according to the disclosure must provide any, letalone all, of the capabilities discussed.

Obtaining the locations of mobile devices that are accessing a wirelessnetwork may be useful for many applications including, for example,emergency calls, personal navigation, consumer asset tracking, locatinga friend or family member, etc. Existing positioning methods includemethods based on measuring radio signals transmitted from a variety ofdevices or entities including satellite vehicles (SVs) and terrestrialradio sources in a wireless network such as base stations and accesspoints. It is expected that standardization for the 5G wireless networkswill include support for various positioning methods, which may utilizereference signals transmitted by base stations in a manner similar towhich LTE wireless networks currently utilize Positioning ReferenceSignals (PRS) and/or Cell-specific Reference Signals (CRS) for positiondetermination.

The description may refer to sequences of actions to be performed, forexample, by elements of a computing device. Various actions describedherein can be performed by specific circuits (e.g., an applicationspecific integrated circuit (ASIC)), by program instructions beingexecuted by one or more processors, or by a combination of both.Sequences of actions described herein may be embodied within anon-transitory computer-readable medium having stored thereon acorresponding set of computer instructions that upon execution wouldcause an associated processor to perform the functionality describedherein. Thus, the various aspects described herein may be embodied in anumber of different forms, all of which are within the scope of thedisclosure, including claimed subject matter.

As used herein, the terms “user equipment” (UE) and “base station” arenot specific to or otherwise limited to any particular Radio AccessTechnology (RAT), unless otherwise noted. In general, such UEs may beany wireless communication device (e.g., a mobile phone, router, tabletcomputer, laptop computer, consumer asset tracking device, Internet ofThings (IoT) device, etc.) used by a user to communicate over a wirelesscommunications network. A UE may be mobile or may (e.g., at certaintimes) be stationary, and may communicate with a Radio Access Network(RAN). As used herein, the term “UE” may be referred to interchangeablyas an “access terminal” or “AT,” a “client device,” a “wireless device,”a “subscriber device,” a “subscriber terminal,” a “subscriber station,”a “user terminal” or UT, a “mobile terminal,” a “mobile station,” a“mobile device,” or variations thereof. Generally, UEs can communicatewith a core network via a RAN, and through the core network the UEs canbe connected with external networks such as the Internet and with otherUEs. Of course, other mechanisms of connecting to the core networkand/or the Internet are also possible for the UEs, such as over wiredaccess networks, WiFi networks (e.g., based on IEEE 802.11, etc.) and soon.

A base station may operate according to one of several RATs incommunication with UEs depending on the network in which it is deployed.Examples of a base station include an Access Point (AP), a Network Node,a NodeB, an evolved NodeB (eNB), or a general Node B (gNodeB, gNB). Inaddition, in some systems a base station may provide purely edge nodesignaling functions while in other systems it may provide additionalcontrol and/or network management functions.

UEs may be embodied by any of a number of types of devices including butnot limited to printed circuit (PC) cards, compact flash devices,external or internal modems, wireless or wireline phones, smartphones,tablets, consumer asset tracking devices, asset tags, and so on. Acommunication link through which UEs can send signals to a RAN is calledan uplink channel (e.g., a reverse traffic channel, a reverse controlchannel, an access channel, etc.). A communication link through whichthe RAN can send signals to UEs is called a downlink or forward linkchannel (e.g., a paging channel, a control channel, a broadcast channel,a forward traffic channel, etc.). As used herein the term trafficchannel (TCH) can refer to either an uplink/reverse or downlink/forwardtraffic channel.

As used herein, the term “cell” or “sector” may correspond to one of aplurality of cells of a base station, or to the base station itself,depending on the context. The term “cell” may refer to a logicalcommunication entity used for communication with a base station (forexample, over a carrier), and may be associated with an identifier fordistinguishing neighboring cells (for example, a physical cellidentifier (PCID), a virtual cell identifier (VCID)) operating via thesame or a different carrier. In some examples, a carrier may supportmultiple cells, and different cells may be configured according todifferent protocol types (for example, machine-type communication (MTC),narrowband Internet-of-Things (NB-IoT), enhanced mobile broadband(eMBB), or others) that may provide access for different types ofdevices. In some examples, the term “cell” may refer to a portion of ageographic coverage area (for example, a sector) over which the logicalentity operates.

Referring to FIG. 1 , an example of a communication system 100 includesa UE 105, a UE 106, a Radio Access Network (RAN), here a FifthGeneration (5G) Next Generation (NG) RAN (NG-RAN) 135, a 5G Core Network(5GC) 140, and a server 150. The UE 105 and/or the UE 106 may be, e.g.,an IoT device, a location tracker device, a cellular telephone, avehicle (e.g., a car, a truck, a bus, a boat, etc.), or other device. A5G network may also be referred to as a New Radio (NR) network; NG-RAN135 may be referred to as a 5G RAN or as an NR RAN; and 5GC 140 may bereferred to as an NG Core network (NGC). Standardization of an NG-RANand 5GC is ongoing in the 3rd Generation Partnership Project (3GPP).Accordingly, the NG-RAN 135 and the 5GC 140 may conform to current orfuture standards for 5G support from 3GPP. The NG-RAN 135 may be anothertype of RAN, e.g., a 3G RAN, a 4G Long Term Evolution (LTE) RAN, etc.The UE 106 may be configured and coupled similarly to the UE 105 to sendand/or receive signals to/from similar other entities in the system 100,but such signaling is not indicated in FIG. 1 for the sake of simplicityof the figure. Similarly, the discussion focuses on the UE 105 for thesake of simplicity. The communication system 100 may utilize informationfrom a constellation 185 containing a satellite vehicle (SV) 190, an SV191, an SV 192, and an SV 193 for a Satellite Positioning System (SPS)(e.g., a Global Navigation Satellite System (GNSS)) like the GlobalPositioning System (GPS), the Global Navigation Satellite System(GLONASS), Galileo, or Beidou or some other local or regional SPS suchas the Indian Regional Navigational Satellite System (IRNSS), theEuropean Geostationary Navigation Overlay Service (EGNOS), or the WideArea Augmentation System (WAAS). Additional components of thecommunication system 100 are described below. The communication system100 may include additional or alternative components.

As shown in FIG. 1 , the NG-RAN 135 includes NR nodeBs (gNBs) 110 a, 110b, and a next generation eNodeB (ng-eNB) 114, and the 5GC 140 includesan Access and Mobility Management Function (AMF) 115, a SessionManagement Function (SMF) 117, a Location Management Function (LMF) 120,and a Gateway Mobile Location Center (GMLC) 125. The gNBs 110 a, 110 band the ng-eNB 114 are communicatively coupled to each other, are eachconfigured to bi-directionally wirelessly communicate with the UE 105,and are each communicatively coupled to, and configured tobi-directionally communicate with, the AMF 115. The gNBs 110 a, 110 b,and the ng-eNB 114 may be referred to as base stations (BSs). The AMF115, the SMF 117, the LMF 120, and the GMLC 125 are communicativelycoupled to each other, and the GMLC is communicatively coupled to anexternal client 130. The SMF 117 may serve as an initial contact pointof a Service Control Function (SCF) (not shown) to create, control, anddelete media sessions. Base stations such as the gNBs 110 a, 110 band/or the ng-eNB 114 may be a macro cell (e.g., a high-power cellularbase station), or a small cell (e.g., a low-power cellular basestation), or an access point (e.g., a short-range base stationconfigured to communicate with short-range technology such as WiFi,WiFi-Direct (WiFi-D), Bluetooth®, Bluetooth®-low energy (BLE), Zigbee,etc. One or more BSs, e.g., one or more of the gNBs 110 a, 110 b and/orthe ng-eNB 114 may be configured to communicate with the UE 105 viamultiple carriers. Each of the gNBs 110 a, 110 b and the ng-eNB 114 mayprovide communication coverage for a respective geographic region, e.g.a cell. Each cell may be partitioned into multiple sectors as a functionof the base station antennas.

FIG. 1 provides a generalized illustration of various components, any orall of which may be utilized as appropriate, and each of which may beduplicated or omitted as necessary. Specifically, although one UE 105 isillustrated, many UEs (e.g., hundreds, thousands, millions, etc.) may beutilized in the communication system 100. Similarly, the communicationsystem 100 may include a larger (or smaller) number of SVs (i.e., moreor fewer than the four SVs 190-193 shown), gNBs 110 a, 110 b, ng-eNBs114, AMFs 115, external clients 130, and/or other components. Theillustrated connections that connect the various components in thecommunication system 100 include data and signaling connections whichmay include additional (intermediary) components, direct or indirectphysical and/or wireless connections, and/or additional networks.Furthermore, components may be rearranged, combined, separated,substituted, and/or omitted, depending on desired functionality.

While FIG. 1 illustrates a 5G-based network, similar networkimplementations and configurations may be used for other communicationtechnologies, such as 3G, Long Term Evolution (LTE), etc.Implementations described herein (be they for 5G technology and/or forone or more other communication technologies and/or protocols) may beused to transmit (or broadcast) directional synchronization signals,receive and measure directional signals at UEs (e.g., the UE 105) and/orprovide location assistance to the UE 105 (via the GMLC 125 or otherlocation server) and/or compute a location for the UE 105 at alocation-capable device such as the UE 105, the gNB 110 a, 110 b, or theLMF 120 based on measurement quantities received at the UE 105 for suchdirectionally-transmitted signals. The gateway mobile location center(GMLC) 125, the location management function (LMF) 120, the access andmobility management function (AMF) 115, the SMF 117, the ng-eNB (eNodeB)114 and the gNBs (gNodeBs) 110 a, 110 b are examples and may, in variousembodiments, be replaced by or include various other location serverfunctionality and/or base station functionality respectively.

The system 100 is capable of wireless communication in that componentsof the system 100 can communicate with one another (at least some timesusing wireless connections) directly or indirectly, e.g., via the gNBs110 a, 110 b, the ng-eNB 114, and/or the 5GC 140 (and/or one or moreother devices not shown, such as one or more other base transceiverstations). For indirect communications, the communications may bealtered during transmission from one entity to another, e.g., to alterheader information of data packets, to change format, etc. The UE 105may include multiple UEs and may be a mobile wireless communicationdevice, but may communicate wirelessly and via wired connections. The UE105 may be any of a variety of devices, e.g., a smartphone, a tabletcomputer, a vehicle-based device, etc., but these are examples as the UE105 is not required to be any of these configurations, and otherconfigurations of UEs may be used. Other UEs may include wearabledevices (e.g., smart watches, smart jewelry, smart glasses or headsets,etc.). Still other UEs may be used, whether currently existing ordeveloped in the future. Further, other wireless devices (whether mobileor not) may be implemented within the system 100 and may communicatewith each other and/or with the UE 105, the gNBs 110 a, 110 b, theng-eNB 114, the 5GC 140, and/or the external client 130. For example,such other devices may include internet of thing (IoT) devices, medicaldevices, home entertainment and/or automation devices, etc. The 5GC 140may communicate with the external client 130 (e.g., a computer system),e.g., to allow the external client 130 to request and/or receivelocation information regarding the UE 105 (e.g., via the GMLC 125).

The UE 105 or other devices may be configured to communicate in variousnetworks and/or for various purposes and/or using various technologies(e.g., 5G, Wi-Fi communication, multiple frequencies of Wi-Ficommunication, satellite positioning, one or more types ofcommunications (e.g., GSM (Global System for Mobiles), CDMA (CodeDivision Multiple Access), LTE (Long-Term Evolution), V2X(Vehicle-to-Everything, e.g., V2P (Vehicle-to-Pedestrian), V2I(Vehicle-to-Infrastructure), V2V (Vehicle-to-Vehicle), etc.), IEEE802.11p, etc.). V2X communications may be cellular (Cellular-V2X(C-V2X)) and/or WiFi (e.g., DSRC (Dedicated Short-Range Connection)).The system 100 may support operation on multiple carriers (waveformsignals of different frequencies). Multi-carrier transmitters cantransmit modulated signals simultaneously on the multiple carriers. Eachmodulated signal may be a Code Division Multiple Access (CDMA) signal, aTime Division Multiple Access (TDMA) signal, an Orthogonal FrequencyDivision Multiple Access (OFDMA) signal, a Single-Carrier FrequencyDivision Multiple Access (SC-FDMA) signal, etc. Each modulated signalmay be sent on a different carrier and may carry pilot, overheadinformation, data, etc. The UEs 105, 106 may communicate with each otherthrough UE-to-UE sidelink (SL) communications by transmitting over oneor more sidelink channels such as a physical sidelink synchronizationchannel (PSSCH), a physical sidelink broadcast channel (PSBCH), or aphysical sidelink control channel (PSCCH).

The UE 105 may comprise and/or may be referred to as a device, a mobiledevice, a wireless device, a mobile terminal, a terminal, a mobilestation (MS), a Secure User Plane Location (SUPL) Enabled Terminal(SET), or by some other name. Moreover, the UE 105 may correspond to acellphone, smartphone, laptop, tablet, PDA, consumer asset trackingdevice, navigation device, Internet of Things (IoT) device, healthmonitors, security systems, smart city sensors, smart meters, wearabletrackers, or some other portable or moveable device. Typically, thoughnot necessarily, the UE 105 may support wireless communication using oneor more Radio Access Technologies (RATs) such as Global System forMobile communication (GSM), Code Division Multiple Access (CDMA),Wideband CDMA (WCDMA), LTE, High Rate Packet Data (HRPD), IEEE 802.11WiFi (also referred to as Wi-Fi), Bluetooth® (BT), WorldwideInteroperability for Microwave Access (WiMAX), 5G new radio (NR) (e.g.,using the NG-RAN 135 and the 5GC 140), etc. The UE 105 may supportwireless communication using a Wireless Local Area Network (WLAN) whichmay connect to other networks (e.g., the Internet) using a DigitalSubscriber Line (DSL) or packet cable, for example. The use of one ormore of these RATs may allow the UE 105 to communicate with the externalclient 130 (e.g., via elements of the 5GC 140 not shown in FIG. 1 , orpossibly via the GMLC 125) and/or allow the external client 130 toreceive location information regarding the UE 105 (e.g., via the GMLC125).

The UE 105 may include a single entity or may include multiple entitiessuch as in a personal area network where a user may employ audio, videoand/or data I/O (input/output) devices and/or body sensors and aseparate wireline or wireless modem. An estimate of a location of the UE105 may be referred to as a location, location estimate, location fix,fix, position, position estimate, or position fix, and may begeographic, thus providing location coordinates for the UE 105 (e.g.,latitude and longitude) which may or may not include an altitudecomponent (e.g., height above sea level, height above or depth belowground level, floor level, or basement level). Alternatively, a locationof the UE 105 may be expressed as a civic location (e.g., as a postaladdress or the designation of some point or small area in a buildingsuch as a particular room or floor). A location of the UE 105 may beexpressed as an area or volume (defined either geographically or incivic form) within which the UE 105 is expected to be located with someprobability or confidence level (e.g., 67%, 95%, etc.). A location ofthe UE 105 may be expressed as a relative location comprising, forexample, a distance and direction from a known location. The relativelocation may be expressed as relative coordinates (e.g., X, Y (and Z)coordinates) defined relative to some origin at a known location whichmay be defined, e.g., geographically, in civic terms, or by reference toa point, area, or volume, e.g., indicated on a map, floor plan, orbuilding plan. In the description contained herein, the use of the termlocation may comprise any of these variants unless indicated otherwise.When computing the location of a UE, it is common to solve for local x,y, and possibly z coordinates and then, if desired, convert the localcoordinates into absolute coordinates (e.g., for latitude, longitude,and altitude above or below mean sea level).

The UE 105 may be configured to communicate with other entities usingone or more of a variety of technologies. The UE 105 may be configuredto connect indirectly to one or more communication networks via one ormore device-to-device (D2D) peer-to-peer (P2P) links. The D2D P2P linksmay be supported with any appropriate D2D radio access technology (RAT),such as LTE Direct (LTE-D), WiFi Direct (WiFi-D), Bluetooth®, and so on.One or more of a group of UEs utilizing D2D communications may be withina geographic coverage area of a Transmission/Reception Point (TRP) suchas one or more of the gNBs 110 a, 110 b, and/or the ng-eNB 114. OtherUEs in such a group may be outside such geographic coverage areas, ormay be otherwise unable to receive transmissions from a base station.Groups of UEs communicating via D2D communications may utilize aone-to-many (1:M) system in which each UE may transmit to other UEs inthe group. A TRP may facilitate scheduling of resources for D2Dcommunications. In other cases, D2D communications may be carried outbetween UEs without the involvement of a TRP. One or more of a group ofUEs utilizing D2D communications may be within a geographic coveragearea of a TRP. Other UEs in such a group may be outside such geographiccoverage areas, or be otherwise unable to receive transmissions from abase station. Groups of UEs communicating via D2D communications mayutilize a one-to-many (1:M) system in which each UE may transmit toother UEs in the group. A TRP may facilitate scheduling of resources forD2D communications. In other cases, D2D communications may be carriedout between UEs without the involvement of a TRP.

Base stations (BSs) in the NG-RAN 135 shown in FIG. 1 include NR NodeBs, referred to as the gNBs 110 a and 110 b. Pairs of the gNBs 110 a,110 b in the NG-RAN 135 may be connected to one another via one or moreother gNBs. Access to the 5G network is provided to the UE 105 viawireless communication between the UE 105 and one or more of the gNBs110 a, 110 b, which may provide wireless communications access to the5GC 140 on behalf of the UE 105 using 5G. In FIG. 1 , the serving gNBfor the UE 105 is assumed to be the gNB 110 a, although another gNB(e.g. the gNB 110 b) may act as a serving gNB if the UE 105 moves toanother location or may act as a secondary gNB to provide additionalthroughput and bandwidth to the UE 105.

Base stations (BSs) in the NG-RAN 135 shown in FIG. 1 may include theng-eNB 114, also referred to as a next generation evolved Node B. Theng-eNB 114 may be connected to one or more of the gNBs 110 a, 110 b inthe NG-RAN 135, possibly via one or more other gNBs and/or one or moreother ng-eNBs. The ng-eNB 114 may provide LTE wireless access and/orevolved LTE (eLTE) wireless access to the UE 105. One or more of thegNBs 110 a, 110 b and/or the ng-eNB 114 may be configured to function aspositioning-only beacons which may transmit signals to assist withdetermining the position of the UE 105 but may not receive signals fromthe UE 105 or from other UEs.

The gNBs 110 a, 110 b and/or the ng-eNB 114 may each comprise one ormore TRPs. For example, each sector within a cell of a BS may comprise aTRP, although multiple TRPs may share one or more components (e.g.,share a processor but have separate antennas). The system 100 mayinclude macro TRPs exclusively or the system 100 may have TRPs ofdifferent types, e.g., macro, pico, and/or femto TRPs, etc. A macro TRPmay cover a relatively large geographic area (e.g., several kilometersin radius) and may allow unrestricted access by terminals with servicesubscription. A pico TRP may cover a relatively small geographic area(e.g., a pico cell) and may allow unrestricted access by terminals withservice subscription. A femto or home TRP may cover a relatively smallgeographic area (e.g., a femto cell) and may allow restricted access byterminals having association with the femto cell (e.g., terminals forusers in a home).

Each of the gNBs 110 a, 110 b and/or the ng-eNB 114 may include a radiounit (RU), a distributed unit (DU), and a central unit (CU). Forexample, the gNB 110 a includes an RU 111, a DU 112, and a CU 113. TheRU 111, DU 112, and CU 113 divide functionality of the gNB 110 a. Whilethe gNB 110 a is shown with a single RU, a single DU, and a single CU, agNB may include one or more RUs, one or more DUs, and/or one or moreCUs. An interface between the CU 113 and the DU 112 is referred to as anF1 interface. The RU 111 is configured to perform digital front end(DFE) functions (e.g., analog-to-digital conversion, filtering, poweramplification, transmission/reception) and digital beamforming, andincludes a portion of the physical (PHY) layer. The RU 111 may performthe DFE using massive multiple input/multiple output (MIMO) and may beintegrated with one or more antennas of the gNB 110 a. The DU 112 hoststhe Radio Link Control (RLC), Medium Access Control (MAC), and physicallayers of the gNB 110 a. One DU can support one or more cells, and eachcell is supported by a single DU. The operation of the DU 112 iscontrolled by the CU 113. The CU 113 is configured to perform functionsfor transferring user data, mobility control, radio access networksharing, positioning, session management, etc. although some functionsare allocated exclusively to the DU 112. The CU 113 hosts the RadioResource Control (RRC), Service Data Adaptation Protocol (SDAP), andPacket Data Convergence Protocol (PDCP) protocols of the gNB 110 a. TheUE 105 may communicate with the CU 113 via RRC, SDAP, and PDCP layers,with the DU 112 via the RLC, MAC, and PHY layers, and with the RU 111via the PHY layer.

As noted, while FIG. 1 depicts nodes configured to communicate accordingto 5G communication protocols, nodes configured to communicate accordingto other communication protocols, such as, for example, an LTE protocolor IEEE 802.11x protocol, may be used. For example, in an Evolved PacketSystem (EPS) providing LTE wireless access to the UE 105, a RAN maycomprise an Evolved Universal Mobile Telecommunications System (UMTS)Terrestrial Radio Access Network (E-UTRAN) which may comprise basestations comprising evolved Node Bs (eNBs). A core network for EPS maycomprise an Evolved Packet Core (EPC). An EPS may comprise an E-UTRANplus EPC, where the E-UTRAN corresponds to the NG-RAN 135 and the EPCcorresponds to the 5GC 140 in FIG. 1 .

The gNBs 110 a, 110 b and the ng-eNB 114 may communicate with the AMF115, which, for positioning functionality, communicates with the LMF120. The AMF 115 may support mobility of the UE 105, including cellchange and handover and may participate in supporting a signalingconnection to the UE 105 and possibly data and voice bearers for the UE105. The LMF 120 may communicate directly with the UE 105, e.g., throughwireless communications, or directly with the gNBs 110 a, 110 b and/orthe ng-eNB 114. The LMF 120 may support positioning of the UE 105 whenthe UE 105 accesses the NG-RAN 135 and may support positionprocedures/methods such as Assisted GNSS (A-GNSS), Observed TimeDifference of Arrival (OTDOA) (e.g., Downlink (DL) OTDOA or Uplink (UL)OTDOA), Round Trip Time (RTT), Multi-Cell RTT, Real Time Kinematic(RTK), Precise Point Positioning (PPP), Differential GNSS (DGNSS),Enhanced Cell ID (E-CID), angle of arrival (AoA), angle of departure(AoD), and/or other position methods. The LMF 120 may process locationservices requests for the UE 105, e.g., received from the AMF 115 orfrom the GMLC 125. The LMF 120 may be connected to the AMF 115 and/or tothe GMLC 125. The LMF 120 may be referred to by other names such as aLocation Manager (LM), Location Function (LF), commercial LMF (CLMF), orvalue added LMF (VLMF). A node/system that implements the LMF 120 mayadditionally or alternatively implement other types of location-supportmodules, such as an Enhanced Serving Mobile Location Center (E-SMLC) ora Secure User Plane Location (SUPL) Location Platform (SLP). At leastpart of the positioning functionality (including derivation of thelocation of the UE 105) may be performed at the UE 105 (e.g., usingsignal measurements obtained by the UE 105 for signals transmitted bywireless nodes such as the gNBs 110 a, 110 b and/or the ng-eNB 114,and/or assistance data provided to the UE 105, e.g. by the LMF 120). TheAMF 115 may serve as a control node that processes signaling between theUE 105 and the 5GC 140, and may provide QoS (Quality of Service) flowand session management. The AMF 115 may support mobility of the UE 105including cell change and handover and may participate in supportingsignaling connection to the UE 105.

The server 150, e.g., a cloud server, is configured to obtain andprovide location estimates of the UE 105 to the external client 130. Theserver 150 may, for example, be configured to run a microservice/servicethat obtains the location estimate of the UE 105. The server 150 may,for example, pull the location estimate from (e.g., by sending alocation request to) the UE 105, one or more of the gNBs 110 a, 110 b(e.g., via the RU 111, the DU 112, and the CU 113) and/or the ng-eNB114, and/or the LMF 120. As another example, the UE 105, one or more ofthe gNBs 110 a, 110 b (e.g., via the RU 111, the DU 112, and the CU113), and/or the LMF 120 may push the location estimate of the UE 105 tothe server 150.

The GMLC 125 may support a location request for the UE 105 received fromthe external client 130 via the server 150 and may forward such alocation request to the AMF 115 for forwarding by the AMF 115 to the LMF120 or may forward the location request directly to the LMF 120. Alocation response from the LMF 120 (e.g., containing a location estimatefor the UE 105) may be returned to the GMLC 125 either directly or viathe AMF 115 and the GMLC 125 may then return the location response(e.g., containing the location estimate) to the external client 130 viathe server 150. The GMLC 125 is shown connected to both the AMF 115 andLMF 120, though may not be connected to the AMF 115 or the LMF 120 insome implementations.

As further illustrated in FIG. 1 , the LMF 120 may communicate with thegNBs 110 a, 110 b and/or the ng-eNB 114 using a New Radio PositionProtocol A (which may be referred to as NPPa or NRPPa), which may bedefined in 3GPP Technical Specification (TS) 38.455. NRPPa may be thesame as, similar to, or an extension of the LTE Positioning Protocol A(LPPa) defined in 3GPP TS 36.455, with NRPPa messages being transferredbetween the gNB 110 a (or the gNB 110 b) and the LMF 120, and/or betweenthe ng-eNB 114 and the LMF 120, via the AMF 115. As further illustratedin FIG. 1 , the LMF 120 and the UE 105 may communicate using an LTEPositioning Protocol (LPP), which may be defined in 3GPP TS 36.355. TheLMF 120 and the UE 105 may also or instead communicate using a New RadioPositioning Protocol (which may be referred to as NPP or NRPP), whichmay be the same as, similar to, or an extension of LPP. Here, LPP and/orNPP messages may be transferred between the UE 105 and the LMF 120 viathe AMF 115 and the serving gNB 110 a, 110 b or the serving ng-eNB 114for the UE 105. For example, LPP and/or NPP messages may be transferredbetween the LMF 120 and the AMF 115 using a 5G Location ServicesApplication Protocol (LCS AP) and may be transferred between the AMF 115and the UE 105 using a 5G Non-Access Stratum (NAS) protocol. The LPPand/or NPP protocol may be used to support positioning of the UE 105using UE-assisted and/or UE-based position methods such as A-GNSS, RTK,OTDOA and/or E-CID. The NRPPa protocol may be used to supportpositioning of the UE 105 using network-based position methods such asE-CID (e.g., when used with measurements obtained by the gNB 110 a, 110b or the ng-eNB 114) and/or may be used by the LMF 120 to obtainlocation related information from the gNBs 110 a, 110 b and/or theng-eNB 114, such as parameters defining directional SS transmissionsfrom the gNBs 110 a, 110 b, and/or the ng-eNB 114. The LMF 120 may beco-located or integrated with a gNB or a TRP, or may be disposed remotefrom the gNB and/or the TRP and configured to communicate directly orindirectly with the gNB and/or the TRP.

With a UE-assisted position method, the UE 105 may obtain locationmeasurements and send the measurements to a location server (e.g., theLMF 120) for computation of a location estimate for the UE 105. Forexample, the location measurements may include one or more of a ReceivedSignal Strength Indication (RSSI), Round Trip signal propagation Time(RTT), Reference Signal Time Difference (RSTD), Reference SignalReceived Power (RSRP) and/or Reference Signal Received Quality (RSRQ)for the gNBs 110 a, 110 b, the ng-eNB 114, and/or a WLAN AP. Thelocation measurements may also or instead include measurements of GNSSpseudorange, code phase, and/or carrier phase for the SVs 190-193.

With a UE-based position method, the UE 105 may obtain locationmeasurements (e.g., which may be the same as or similar to locationmeasurements for a UE-assisted position method) and may compute alocation of the UE 105 (e.g., with the help of assistance data receivedfrom a location server such as the LMF 120 or broadcast by the gNBs 110a, 110 b, the ng-eNB 114, or other base stations or APs).

With a network-based position method, one or more base stations (e.g.,the gNBs 110 a, 110 b, and/or the ng-eNB 114) or APs may obtain locationmeasurements (e.g., measurements of RSSI, RTT, RSRP, RSRQ or Time ofArrival (ToA) for signals transmitted by the UE 105) and/or may receivemeasurements obtained by the UE 105. The one or more base stations orAPs may send the measurements to a location server (e.g., the LMF 120)for computation of a location estimate for the UE 105.

Information provided by the gNBs 110 a, 110 b, and/or the ng-eNB 114 tothe LMF 120 using NRPPa may include timing and configuration informationfor directional SS transmissions and location coordinates. The LMF 120may provide some or all of this information to the UE 105 as assistancedata in an LPP and/or NPP message via the NG-RAN 135 and the 5GC 140.

An LPP or NPP message sent from the LMF 120 to the UE 105 may instructthe UE 105 to do any of a variety of things depending on desiredfunctionality. For example, the LPP or NPP message could contain aninstruction for the UE 105 to obtain measurements for GNSS (or A-GNSS),WLAN, E-CID, and/or OTDOA (or some other position method). In the caseof E-CID, the LPP or NPP message may instruct the UE 105 to obtain oneor more measurement quantities (e.g., beam ID, beam width, mean angle,RSRP, RSRQ measurements) of directional signals transmitted withinparticular cells supported by one or more of the gNBs 110 a, 110 b,and/or the ng-eNB 114 (or supported by some other type of base stationsuch as an eNB or WiFi AP). The UE 105 may send the measurementquantities back to the LMF 120 in an LPP or NPP message (e.g., inside a5G NAS message) via the serving gNB 110 a (or the serving ng-eNB 114)and the AMF 115.

As noted, while the communication system 100 is described in relation to5G technology, the communication system 100 may be implemented tosupport other communication technologies, such as GSM, WCDMA, LTE, etc.,that are used for supporting and interacting with mobile devices such asthe UE 105 (e.g., to implement voice, data, positioning, and otherfunctionalities). In some such embodiments, the 5GC 140 may beconfigured to control different air interfaces. For example, the 5GC 140may be connected to a WLAN using a Non-3GPP InterWorking Function(N3IWF, not shown FIG. 1 ) in the 5GC 140. For example, the WLAN maysupport IEEE 802.11 WiFi access for the UE 105 and may comprise one ormore WiFi APs. Here, the N3IWF may connect to the WLAN and to otherelements in the 5GC 140 such as the AMF 115. In some embodiments, boththe NG-RAN 135 and the 5GC 140 may be replaced by one or more other RANsand one or more other core networks. For example, in an EPS, the NG-RAN135 may be replaced by an E-UTRAN containing eNBs and the 5GC 140 may bereplaced by an EPC containing a Mobility Management Entity (MME) inplace of the AMF 115, an E-SMLC in place of the LMF 120, and a GMLC thatmay be similar to the GMLC 125. In such an EPS, the E-SMLC may use LPPain place of NRPPa to send and receive location information to and fromthe eNBs in the E-UTRAN and may use LPP to support positioning of the UE105. In these other embodiments, positioning of the UE 105 usingdirectional PRSs may be supported in an analogous manner to thatdescribed herein for a 5G network with the difference that functions andprocedures described herein for the gNBs 110 a, 110 b, the ng-eNB 114,the AMF 115, and the LMF 120 may, in some cases, apply instead to othernetwork elements such eNBs, WiFi APs, an MME, and an E-SMLC.

As noted, in some embodiments, positioning functionality may beimplemented, at least in part, using the directional SS beams, sent bybase stations (such as the gNBs 110 a, 110 b, and/or the ng-eNB 114)that are within range of the UE whose position is to be determined(e.g., the UE 105 of FIG. 1 ). The UE may, in some instances, use thedirectional SS beams from a plurality of base stations (such as the gNBs110 a, 110 b, the ng-eNB 114, etc.) to compute the UE's position.

Referring also to FIG. 2 , a UE 200 is an example of one of the UEs 105,106 and comprises a computing platform including a processor 210, memory211 including software (SW) 212, one or more sensors 213, a transceiverinterface 214 for a transceiver 215 (that includes a wirelesstransceiver 240 and a wired transceiver 250), a user interface 216, aSatellite Positioning System (SPS) receiver 217, a camera 218, and aposition device (PD) 219. The processor 210, the memory 211, thesensor(s) 213, the transceiver interface 214, the user interface 216,the SPS receiver 217, the camera 218, and the position device 219 may becommunicatively coupled to each other by a bus 220 (which may beconfigured, e.g., for optical and/or electrical communication). One ormore of the shown apparatus (e.g., the camera 218, the position device219, and/or one or more of the sensor(s) 213, etc.) may be omitted fromthe UE 200. The processor 210 may include one or more intelligenthardware devices, e.g., a central processing unit (CPU), amicrocontroller, an application specific integrated circuit (ASIC), etc.The processor 210 may comprise multiple processors including ageneral-purpose/application processor 230, a Digital Signal Processor(DSP) 231, a modem processor 232, a video processor 233, and/or a sensorprocessor 234. One or more of the processors 230-234 may comprisemultiple devices (e.g., multiple processors). For example, the sensorprocessor 234 may comprise, e.g., processors for RF (radio frequency)sensing (with one or more (cellular) wireless signals transmitted andreflection(s) used to identify, map, and/or track an object), and/orultrasound, etc. The modem processor 232 may support dual SIM/dualconnectivity (or even more SIMs). For example, a SIM (SubscriberIdentity Module or Subscriber Identification Module) may be used by anOriginal Equipment Manufacturer (OEM), and another SIM may be used by anend user of the UE 200 for connectivity. The memory 211 is anon-transitory storage medium that may include random access memory(RAM), flash memory, disc memory, and/or read-only memory (ROM), etc.The memory 211 stores the software 212 which may be processor-readable,processor-executable software code containing instructions that areconfigured to, when executed, cause the processor 210 to perform variousfunctions described herein. Alternatively, the software 212 may not bedirectly executable by the processor 210 but may be configured to causethe processor 210, e.g., when compiled and executed, to perform thefunctions. The description may refer to the processor 210 performing afunction, but this includes other implementations such as where theprocessor 210 executes software and/or firmware. The description mayrefer to the processor 210 performing a function as shorthand for one ormore of the processors 230-234 performing the function. The descriptionmay refer to the UE 200 performing a function as shorthand for one ormore appropriate components of the UE 200 performing the function. Theprocessor 210 may include a memory with stored instructions in additionto and/or instead of the memory 211. Functionality of the processor 210is discussed more fully below.

The configuration of the UE 200 shown in FIG. 2 is an example and notlimiting of the disclosure, including the claims, and otherconfigurations may be used. For example, an example configuration of theUE includes one or more of the processors 230-234 of the processor 210,the memory 211, and the wireless transceiver 240. Other exampleconfigurations include one or more of the processors 230-234 of theprocessor 210, the memory 211, a wireless transceiver, and one or moreof the sensor(s) 213, the user interface 216, the SPS receiver 217, thecamera 218, the PD 219, and/or a wired transceiver.

The UE 200 may comprise the modem processor 232 that may be capable ofperforming baseband processing of signals received and down-converted bythe transceiver 215 and/or the SPS receiver 217. The modem processor 232may perform baseband processing of signals to be upconverted fortransmission by the transceiver 215. Also or alternatively, basebandprocessing may be performed by the processor 230 and/or the DSP 231.Other configurations, however, may be used to perform basebandprocessing.

The UE 200 may include the sensor(s) 213 that may include, for example,one or more of various types of sensors such as one or more inertialsensors, one or more magnetometers, one or more environment sensors, oneor more optical sensors, one or more weight sensors, and/or one or moreradio frequency (RF) sensors, etc. An inertial measurement unit (IMU)may comprise, for example, one or more accelerometers (e.g.,collectively responding to acceleration of the UE 200 in threedimensions) and/or one or more gyroscopes (e.g., three-dimensionalgyroscope(s)). The sensor(s) 213 may include one or more magnetometers(e.g., three-dimensional magnetometer(s)) to determine orientation(e.g., relative to magnetic north and/or true north) that may be usedfor any of a variety of purposes, e.g., to support one or more compassapplications. The environment sensor(s) may comprise, for example, oneor more temperature sensors, one or more barometric pressure sensors,one or more ambient light sensors, one or more camera imagers, and/orone or more microphones, etc. The sensor(s) 213 may generate analogand/or digital signals indications of which may be stored in the memory211 and processed by the DSP 231 and/or the processor 230 in support ofone or more applications such as, for example, applications directed topositioning and/or navigation operations.

The sensor(s) 213 may be used in relative location measurements,relative location determination, motion determination, etc. Informationdetected by the sensor(s) 213 may be used for motion detection, relativedisplacement, dead reckoning, sensor-based location determination,and/or sensor-assisted location determination. The sensor(s) 213 may beuseful to determine whether the UE 200 is fixed (stationary) or mobileand/or whether to report certain useful information to the LMF 120regarding the mobility of the UE 200. For example, based on theinformation obtained/measured by the sensor(s) 213, the UE 200 maynotify/report to the LMF 120 that the UE 200 has detected movements orthat the UE 200 has moved, and report the relative displacement/distance(e.g., via dead reckoning, or sensor-based location determination, orsensor-assisted location determination enabled by the sensor(s) 213). Inanother example, for relative positioning information, the sensors/IMUcan be used to determine the angle and/or orientation of the otherdevice with respect to the UE 200, etc.

The IMU may be configured to provide measurements about a direction ofmotion and/or a speed of motion of the UE 200, which may be used inrelative location determination. For example, one or more accelerometersand/or one or more gyroscopes of the IMU may detect, respectively, alinear acceleration and a speed of rotation of the UE 200. The linearacceleration and speed of rotation measurements of the UE 200 may beintegrated over time to determine an instantaneous direction of motionas well as a displacement of the UE 200. The instantaneous direction ofmotion and the displacement may be integrated to track a location of theUE 200. For example, a reference location of the UE 200 may bedetermined, e.g., using the SPS receiver 217 (and/or by some othermeans) for a moment in time and measurements from the accelerometer(s)and gyroscope(s) taken after this moment in time may be used in deadreckoning to determine present location of the UE 200 based on movement(direction and distance) of the UE 200 relative to the referencelocation.

The magnetometer(s) may determine magnetic field strengths in differentdirections which may be used to determine orientation of the UE 200. Forexample, the orientation may be used to provide a digital compass forthe UE 200. The magnetometer(s) may include a two-dimensionalmagnetometer configured to detect and provide indications of magneticfield strength in two orthogonal dimensions. The magnetometer(s) mayinclude a three-dimensional magnetometer configured to detect andprovide indications of magnetic field strength in three orthogonaldimensions. The magnetometer(s) may provide means for sensing a magneticfield and providing indications of the magnetic field, e.g., to theprocessor 210.

The transceiver 215 may include a wireless transceiver 240 and a wiredtransceiver 250 configured to communicate with other devices throughwireless connections and wired connections, respectively. For example,the wireless transceiver 240 may include a wireless transmitter 242 anda wireless receiver 244 coupled to an antenna 246 for transmitting(e.g., on one or more uplink channels and/or one or more sidelinkchannels) and/or receiving (e.g., on one or more downlink channelsand/or one or more sidelink channels) wireless signals 248 andtransducing signals from the wireless signals 248 to wired (e.g.,electrical and/or optical) signals and from wired (e.g., electricaland/or optical) signals to the wireless signals 248. Thus, the wirelesstransmitter 242 may include multiple transmitters that may be discretecomponents or combined/integrated components, and/or the wirelessreceiver 244 may include multiple receivers that may be discretecomponents or combined/integrated components. The wireless transceiver240 may be configured to communicate signals (e.g., with TRPs and/or oneor more other devices) according to a variety of radio accesstechnologies (RATs) such as 5G New Radio (NR), GSM (Global System forMobiles), UMTS (Universal Mobile Telecommunications System), AMPS(Advanced Mobile Phone System), CDMA (Code Division Multiple Access),WCDMA (Wideband CDMA), LTE (Long-Term Evolution), LTE Direct (LTE-D),3GPP LTE-V2X (PC5), IEEE 802.11 (including IEEE 802.11p), WiFi, WiFiDirect (WiFi-D), Bluetooth®, Zigbee etc. New Radio may use mm-wavefrequencies and/or sub-6 GHz frequencies. The wired transceiver 250 mayinclude a wired transmitter 252 and a wired receiver 254 configured forwired communication, e.g., a network interface that may be utilized tocommunicate with the NG-RAN 135 to send communications to, and receivecommunications from, the NG-RAN 135. The wired transmitter 252 mayinclude multiple transmitters that may be discrete components orcombined/integrated components, and/or the wired receiver 254 mayinclude multiple receivers that may be discrete components orcombined/integrated components. The wired transceiver 250 may beconfigured, e.g., for optical communication and/or electricalcommunication. The transceiver 215 may be communicatively coupled to thetransceiver interface 214, e.g., by optical and/or electricalconnection. The transceiver interface 214 may be at least partiallyintegrated with the transceiver 215. The wireless transmitter 242, thewireless receiver 244, and/or the antenna 246 may include multipletransmitters, multiple receivers, and/or multiple antennas,respectively, for sending and/or receiving, respectively, appropriatesignals.

The user interface 216 may comprise one or more of several devices suchas, for example, a speaker, microphone, display device, vibrationdevice, keyboard, touch screen, etc. The user interface 216 may includemore than one of any of these devices. The user interface 216 may beconfigured to enable a user to interact with one or more applicationshosted by the UE 200. For example, the user interface 216 may storeindications of analog and/or digital signals in the memory 211 to beprocessed by DSP 231 and/or the general-purpose processor 230 inresponse to action from a user. Similarly, applications hosted on the UE200 may store indications of analog and/or digital signals in the memory211 to present an output signal to a user. The user interface 216 mayinclude an audio input/output (I/O) device comprising, for example, aspeaker, a microphone, digital-to-analog circuitry, analog-to-digitalcircuitry, an amplifier and/or gain control circuitry (including morethan one of any of these devices). Other configurations of an audio I/Odevice may be used. Also or alternatively, the user interface 216 maycomprise one or more touch sensors responsive to touching and/orpressure, e.g., on a keyboard and/or touch screen of the user interface216.

The SPS receiver 217 (e.g., a Global Positioning System (GPS) receiver)may be capable of receiving and acquiring SPS signals 260 via an SPSantenna 262. The SPS antenna 262 is configured to transduce the SPSsignals 260 from wireless signals to wired signals, e.g., electrical oroptical signals, and may be integrated with the antenna 246. The SPSreceiver 217 may be configured to process, in whole or in part, theacquired SPS signals 260 for estimating a location of the UE 200. Forexample, the SPS receiver 217 may be configured to determine location ofthe UE 200 by trilateration using the SPS signals 260. Thegeneral-purpose processor 230, the memory 211, the DSP 231 and/or one ormore specialized processors (not shown) may be utilized to processacquired SPS signals, in whole or in part, and/or to calculate anestimated location of the UE 200, in conjunction with the SPS receiver217. The memory 211 may store indications (e.g., measurements) of theSPS signals 260 and/or other signals (e.g., signals acquired from thewireless transceiver 240) for use in performing positioning operations.The general-purpose processor 230, the DSP 231, and/or one or morespecialized processors, and/or the memory 211 may provide or support alocation engine for use in processing measurements to estimate alocation of the UE 200.

The UE 200 may include the camera 218 for capturing still or movingimagery. The camera 218 may comprise, for example, an imaging sensor(e.g., a charge coupled device or a CMOS imager), a lens,analog-to-digital circuitry, frame buffers, etc. Additional processing,conditioning, encoding, and/or compression of signals representingcaptured images may be performed by the general-purpose processor 230and/or the DSP 231. Also or alternatively, the video processor 233 mayperform conditioning, encoding, compression, and/or manipulation ofsignals representing captured images. The video processor 233 maydecode/decompress stored image data for presentation on a display device(not shown), e.g., of the user interface 216.

The position device (PD) 219 may be configured to determine a positionof the UE 200, motion of the UE 200, and/or relative position of the UE200, and/or time. For example, the PD 219 may communicate with, and/orinclude some or all of, the SPS receiver 217. The PD 219 may work inconjunction with the processor 210 and the memory 211 as appropriate toperform at least a portion of one or more positioning methods, althoughthe description herein may refer to the PD 219 being configured toperform, or performing, in accordance with the positioning method(s).The PD 219 may also or alternatively be configured to determine locationof the UE 200 using terrestrial-based signals (e.g., at least some ofthe signals 248) for trilateration, for assistance with obtaining andusing the SPS signals 260, or both. The PD 219 may be configured to useone or more other techniques (e.g., relying on the UE's self-reportedlocation (e.g., part of the UE's position beacon)) for determining thelocation of the UE 200, and may use a combination of techniques (e.g.,SPS and terrestrial positioning signals) to determine the location ofthe UE 200. The PD 219 may include one or more of the sensors 213 (e.g.,gyroscope(s), accelerometer(s), magnetometer(s), etc.) that may senseorientation and/or motion of the UE 200 and provide indications thereofthat the processor 210 (e.g., the processor 230 and/or the DSP 231) maybe configured to use to determine motion (e.g., a velocity vector and/oran acceleration vector) of the UE 200. The PD 219 may be configured toprovide indications of uncertainty and/or error in the determinedposition and/or motion. Functionality of the PD 219 may be provided in avariety of manners and/or configurations, e.g., by the generalpurpose/application processor 230, the transceiver 215, the SPS receiver217, and/or another component of the UE 200, and may be provided byhardware, software, firmware, or various combinations thereof.

Referring also to FIG. 3 , an example of a TRP 300 of the gNBs 110 a,110 b and/or the ng-eNB 114 comprises a computing platform including aprocessor 310, memory 311 including software (SW) 312, and a transceiver315. The processor 310, the memory 311, and the transceiver 315 may becommunicatively coupled to each other by a bus 320 (which may beconfigured, e.g., for optical and/or electrical communication). One ormore of the shown apparatus (e.g., a wireless interface) may be omittedfrom the TRP 300. The processor 310 may include one or more intelligenthardware devices, e.g., a central processing unit (CPU), amicrocontroller, an application specific integrated circuit (ASIC), etc.The processor 310 may comprise multiple processors (e.g., including ageneral-purpose/application processor, a DSP, a modem processor, a videoprocessor, and/or a sensor processor as shown in FIG. 2 ). The memory311 is a non-transitory storage medium that may include random accessmemory (RAM)), flash memory, disc memory, and/or read-only memory (ROM),etc. The memory 311 stores the software 312 which may beprocessor-readable, processor-executable software code containinginstructions that are configured to, when executed, cause the processor310 to perform various functions described herein. Alternatively, thesoftware 312 may not be directly executable by the processor 310 but maybe configured to cause the processor 310, e.g., when compiled andexecuted, to perform the functions.

The description may refer to the processor 310 performing a function,but this includes other implementations such as where the processor 310executes software and/or firmware. The description may refer to theprocessor 310 performing a function as shorthand for one or more of theprocessors contained in the processor 310 performing the function. Thedescription may refer to the TRP 300 performing a function as shorthandfor one or more appropriate components (e.g., the processor 310 and thememory 311) of the TRP 300 (and thus of one of the gNBs 110 a, 110 band/or the ng-eNB 114) performing the function. The processor 310 mayinclude a memory with stored instructions in addition to and/or insteadof the memory 311. Functionality of the processor 310 is discussed morefully below.

The transceiver 315 may include a wireless transceiver 340 and/or awired transceiver 350 configured to communicate with other devicesthrough wireless connections and wired connections, respectively. Forexample, the wireless transceiver 340 may include a wireless transmitter342 and a wireless receiver 344 coupled to one or more antennas 346 fortransmitting (e.g., on one or more uplink channels and/or one or moredownlink channels) and/or receiving (e.g., on one or more downlinkchannels and/or one or more uplink channels) wireless signals 348 andtransducing signals from the wireless signals 348 to wired (e.g.,electrical and/or optical) signals and from wired (e.g., electricaland/or optical) signals to the wireless signals 348. Thus, the wirelesstransmitter 342 may include multiple transmitters that may be discretecomponents or combined/integrated components, and/or the wirelessreceiver 344 may include multiple receivers that may be discretecomponents or combined/integrated components. The wireless transceiver340 may be configured to communicate signals (e.g., with the UE 200, oneor more other UEs, and/or one or more other devices) according to avariety of radio access technologies (RATs) such as 5G New Radio (NR),GSM (Global System for Mobiles), UMTS (Universal MobileTelecommunications System), AMPS (Advanced Mobile Phone System), CDMA(Code Division Multiple Access), WCDMA (Wideband CDMA), LTE (Long-TermEvolution), LTE Direct (LTE-D), 3GPP LTE-V2X (PC5), IEEE 802.11(including IEEE 802.11p), WiFi, WiFi Direct (WiFi-D), Bluetooth®, Zigbeeetc. The wired transceiver 350 may include a wired transmitter 352 and awired receiver 354 configured for wired communication, e.g., a networkinterface that may be utilized to communicate with the NG-RAN 135 tosend communications to, and receive communications from, the LMF 120,for example, and/or one or more other network entities. The wiredtransmitter 352 may include multiple transmitters that may be discretecomponents or combined/integrated components, and/or the wired receiver354 may include multiple receivers that may be discrete components orcombined/integrated components. The wired transceiver 350 may beconfigured, e.g., for optical communication and/or electricalcommunication.

The configuration of the TRP 300 shown in FIG. 3 is an example and notlimiting of the disclosure, including the claims, and otherconfigurations may be used. For example, the description hereindiscusses that the TRP 300 is configured to perform or performs severalfunctions, but one or more of these functions may be performed by theLMF 120 and/or the UE 200 (i.e., the LMF 120 and/or the UE 200 may beconfigured to perform one or more of these functions).

Referring also to FIG. 4 , a server 400, of which the LMF 120 is anexample, comprises a computing platform including a processor 410,memory 411 including software (SW) 412, and a transceiver 415. Theprocessor 410, the memory 411, and the transceiver 415 may becommunicatively coupled to each other by a bus 420 (which may beconfigured, e.g., for optical and/or electrical communication). One ormore of the shown apparatus (e.g., a wireless interface) may be omittedfrom the server 400. The processor 410 may include one or moreintelligent hardware devices, e.g., a central processing unit (CPU), amicrocontroller, an application specific integrated circuit (ASIC), etc.The processor 410 may comprise multiple processors (e.g., including ageneral-purpose/application processor, a DSP, a modem processor, a videoprocessor, and/or a sensor processor as shown in FIG. 2 ). The memory411 is a non-transitory storage medium that may include random accessmemory (RAM)), flash memory, disc memory, and/or read-only memory (ROM),etc. The memory 411 stores the software 412 which may beprocessor-readable, processor-executable software code containinginstructions that are configured to, when executed, cause the processor410 to perform various functions described herein. Alternatively, thesoftware 412 may not be directly executable by the processor 410 but maybe configured to cause the processor 410, e.g., when compiled andexecuted, to perform the functions. The description may refer to theprocessor 410 performing a function, but this includes otherimplementations such as where the processor 410 executes software and/orfirmware. The description may refer to the processor 410 performing afunction as shorthand for one or more of the processors contained in theprocessor 410 performing the function. The description may refer to theserver 400 performing a function as shorthand for one or moreappropriate components of the server 400 performing the function. Theprocessor 410 may include a memory with stored instructions in additionto and/or instead of the memory 411. Functionality of the processor 410is discussed more fully below.

The transceiver 415 may include a wireless transceiver 440 and/or awired transceiver 450 configured to communicate with other devicesthrough wireless connections and wired connections, respectively. Forexample, the wireless transceiver 440 may include a wireless transmitter442 and a wireless receiver 444 coupled to one or more antennas 446 fortransmitting (e.g., on one or more downlink channels) and/or receiving(e.g., on one or more uplink channels) wireless signals 448 andtransducing signals from the wireless signals 448 to wired (e.g.,electrical and/or optical) signals and from wired (e.g., electricaland/or optical) signals to the wireless signals 448. Thus, the wirelesstransmitter 442 may include multiple transmitters that may be discretecomponents or combined/integrated components, and/or the wirelessreceiver 444 may include multiple receivers that may be discretecomponents or combined/integrated components. The wireless transceiver440 may be configured to communicate signals (e.g., with the UE 200, oneor more other UEs, and/or one or more other devices) according to avariety of radio access technologies (RATs) such as 5G New Radio (NR),GSM (Global System for Mobiles), UMTS (Universal MobileTelecommunications System), AMPS (Advanced Mobile Phone System), CDMA(Code Division Multiple Access), WCDMA (Wideband CDMA), LTE (Long-TermEvolution), LTE Direct (LTE-D), 3GPP LTE-V2X (PC5), IEEE 802.11(including IEEE 802.11p), WiFi, WiFi Direct (WiFi-D), Bluetooth®, Zigbeeetc. The wired transceiver 450 may include a wired transmitter 452 and awired receiver 454 configured for wired communication, e.g., a networkinterface that may be utilized to communicate with the NG-RAN 135 tosend communications to, and receive communications from, the TRP 300,for example, and/or one or more other network entities. The wiredtransmitter 452 may include multiple transmitters that may be discretecomponents or combined/integrated components, and/or the wired receiver454 may include multiple receivers that may be discrete components orcombined/integrated components. The wired transceiver 450 may beconfigured, e.g., for optical communication and/or electricalcommunication.

The description herein may refer to the processor 410 performing afunction, but this includes other implementations such as where theprocessor 410 executes software (stored in the memory 411) and/orfirmware. The description herein may refer to the server 400 performinga function as shorthand for one or more appropriate components (e.g.,the processor 410 and the memory 411) of the server 400 performing thefunction.

The configuration of the server 400 shown in FIG. 4 is an example andnot limiting of the disclosure, including the claims, and otherconfigurations may be used. For example, the wireless transceiver 440may be omitted. Also or alternatively, the description herein discussesthat the server 400 is configured to perform or performs severalfunctions, but one or more of these functions may be performed by theTRP 300 and/or the UE 200 (i.e., the TRP 300 and/or the UE 200 may beconfigured to perform one or more of these functions).

Positioning Techniques

For terrestrial positioning of a UE in cellular networks, techniquessuch as Advanced Forward Link Trilateration (AFLT) and Observed TimeDifference Of Arrival (OTDOA) often operate in “UE-assisted” mode inwhich measurements of reference signals (e.g., PRS, CRS, etc.)transmitted by base stations are taken by the UE and then provided to alocation server. The location server then calculates the position of theUE based on the measurements and known locations of the base stations.Because these techniques use the location server to calculate theposition of the UE, rather than the UE itself, these positioningtechniques are not frequently used in applications such as car orcell-phone navigation, which instead typically rely on satellite-basedpositioning.

A UE may use a Satellite Positioning System (SPS) (a Global NavigationSatellite System (GNSS)) for high-accuracy positioning using precisepoint positioning (PPP) or real time kinematic (RTK) technology. Thesetechnologies use assistance data such as measurements from ground-basedstations. LTE Release 15 allows the data to be encrypted so that the UEssubscribed to the service exclusively can read the information. Suchassistance data varies with time. Thus, a UE subscribed to the servicemay not easily “break encryption” for other UEs by passing on the datato other UEs that have not paid for the subscription. The passing onwould need to be repeated every time the assistance data changes.

In UE-assisted positioning, the UE sends measurements (e.g., TDOA, Angleof Arrival (AoA), etc.) to the positioning server (e.g., LMF/eSMLC). Thepositioning server has the base station almanac (BSA) that containsmultiple ‘entries’ or ‘records’, one record per cell, where each recordcontains geographical cell location but also may include other data. Anidentifier of the ‘record’ among the multiple ‘records’ in the BSA maybe referenced. The BSA and the measurements from the UE may be used tocompute the position of the UE.

In conventional UE-based positioning, a UE computes its own position,thus avoiding sending measurements to the network (e.g., locationserver), which in turn improves latency and scalability. The UE usesrelevant BSA record information (e.g., locations of gNBs (more broadlybase stations)) from the network. The BSA information may be encrypted.But since the BSA information varies much less often than, for example,the PPP or RTK assistance data described earlier, it may be easier tomake the BSA information (compared to the PPP or RTK information)available to UEs that did not subscribe and pay for decryption keys.Transmissions of reference signals by the gNBs make BSA informationpotentially accessible to crowd-sourcing or war-driving, essentiallyenabling BSA information to be generated based on in-the-field and/orover-the-top observations.

Positioning techniques may be characterized and/or assessed based on oneor more criteria such as position determination accuracy and/or latency.Latency is a time elapsed between an event that triggers determinationof position-related data and the availability of that data at apositioning system interface, e.g., an interface of the LMF 120. Atinitialization of a positioning system, the latency for the availabilityof position-related data is called time to first fix (TTFF), and islarger than latencies after the TTFF. An inverse of a time elapsedbetween two consecutive position-related data availabilities is calledan update rate, i.e., the rate at which position-related data aregenerated after the first fix. Latency may depend on processingcapability, e.g., of the UE. For example, a UE may report a processingcapability of the UE as a duration of DL PRS symbols in units of time(e.g., milliseconds) that the UE can process every T amount of time(e.g., T ms) assuming 272 PRB (Physical Resource Block) allocation.Other examples of capabilities that may affect latency are a number ofTRPs from which the UE can process PRS, a number of PRS that the UE canprocess, and a bandwidth of the UE.

One or more of many different positioning techniques (also calledpositioning methods) may be used to determine position of an entity suchas one of the UEs 105, 106. For example, known position-determinationtechniques include RTT, multi-RTT, OTDOA (also called TDOA and includingUL-TDOA and DL-TDOA), Enhanced Cell Identification (E-CID), DL-AoD,UL-AoA, etc. RTT uses a time for a signal to travel from one entity toanother and back to determine a range between the two entities. Therange, plus a known location of a first one of the entities and an anglebetween the two entities (e.g., an azimuth angle) can be used todetermine a location of the second of the entities. In multi-RTT (alsocalled multi-cell RTT), multiple ranges from one entity (e.g., a UE) toother entities (e.g., TRPs) and known locations of the other entitiesmay be used to determine the location of the one entity. In TDOAtechniques, the difference in travel times between one entity and otherentities may be used to determine relative ranges from the otherentities and those, combined with known locations of the other entitiesmay be used to determine the location of the one entity. Angles ofarrival and/or departure may be used to help determine location of anentity. For example, an angle of arrival or an angle of departure of asignal combined with a range between devices (determined using signal,e.g., a travel time of the signal, a received power of the signal, etc.)and a known location of one of the devices may be used to determine alocation of the other device. The angle of arrival or departure may bean azimuth angle relative to a reference direction such as true north.The angle of arrival or departure may be a zenith angle relative todirectly upward from an entity (i.e., relative to radially outward froma center of Earth). E-CID uses the identity of a serving cell, thetiming advance (i.e., the difference between receive and transmit timesat the UE), estimated timing and power of detected neighbor cellsignals, and possibly angle of arrival (e.g., of a signal at the UE fromthe base station or vice versa) to determine location of the UE. InTDOA, the difference in arrival times at a receiving device of signalsfrom different sources along with known locations of the sources andknown offset of transmission times from the sources are used todetermine the location of the receiving device.

In a network-centric RTT estimation, the serving base station instructsthe UE to scan for/receive RTT measurement signals (e.g., PRS) onserving cells of two or more neighboring base stations (and typicallythe serving base station, as at least three base stations are needed).The one of more base stations transmit RTT measurement signals on lowreuse resources (e.g., resources used by the base station to transmitsystem information) allocated by the network (e.g., a location serversuch as the LMF 120). The UE records the arrival time (also referred toas a receive time, a reception time, a time of reception, or a time ofarrival (ToA)) of each RTT measurement signal relative to the UE'scurrent downlink timing (e.g., as derived by the UE from a DL signalreceived from its serving base station), and transmits a common orindividual RTT response message (e.g., SRS (sounding reference signal)for positioning, i.e., UL-PRS) to the one or more base stations (e.g.,when instructed by its serving base station) and may include the timedifference T_(Rx→Tx) (i.e., UE T_(Rx-Tx) or UE_(Rx-Tx)) between the ToAof the RTT measurement signal and the transmission time of the RTTresponse message in a payload of each RTT response message. The RTTresponse message would include a reference signal from which the basestation can deduce the ToA of the RTT response. By comparing thedifference T_(Tx→Rx) between the transmission time of the RTTmeasurement signal from the base station and the ToA of the RTT responseat the base station to the UE-reported time difference T_(Rx→Tx), thebase station can deduce the propagation time between the base stationand the UE, from which the base station can determine the distancebetween the UE and the base station by assuming the speed of lightduring this propagation time.

A UE-centric RTT estimation is similar to the network-based method,except that the UE transmits uplink RTT measurement signal(s) (e.g.,when instructed by a serving base station), which are received bymultiple base stations in the neighborhood of the UE. Each involved basestation responds with a downlink RTT response message, which may includethe time difference between the ToA of the RTT measurement signal at thebase station and the transmission time of the RTT response message fromthe base station in the RTT response message payload.

For both network-centric and UE-centric procedures, the side (network orUE) that performs the RTT calculation typically (though not always)transmits the first message(s) or signal(s) (e.g., RTT measurementsignal(s)), while the other side responds with one or more RTT responsemessage(s) or signal(s) that may include the difference between the ToAof the first message(s) or signal(s) and the transmission time of theRTT response message(s) or signal(s).

A multi-RTT technique may be used to determine position. For example, afirst entity (e.g., a UE) may send out one or more signals (e.g.,unicast, multicast, or broadcast from the base station) and multiplesecond entities (e.g., other TSPs such as base station(s) and/or UE(s))may receive a signal from the first entity and respond to this receivedsignal. The first entity receives the responses from the multiple secondentities. The first entity (or another entity such as an LMF) may usethe responses from the second entities to determine ranges to the secondentities and may use the multiple ranges and known locations of thesecond entities to determine the location of the first entity bytrilateration.

In some instances, additional information may be obtained in the form ofan angle of arrival (AoA) or angle of departure (AoD) that defines astraight-line direction (e.g., which may be in a horizontal plane or inthree dimensions) or possibly a range of directions (e.g., for the UEfrom the locations of base stations). The intersection of two directionscan provide another estimate of the location for the UE.

For positioning techniques using PRS (Positioning Reference Signal)signals (e.g., TDOA and RTT), PRS signals sent by multiple TRPs aremeasured and the arrival times of the signals, known transmission times,and known locations of the TRPs used to determine ranges from a UE tothe TRPs. For example, an RSTD (Reference Signal Time Difference) may bedetermined for PRS signals received from multiple TRPs and used in aTDOA technique to determine position (location) of the UE. A positioningreference signal may be referred to as a PRS or a PRS signal. The PRSsignals are typically sent using the same power and PRS signals with thesame signal characteristics (e.g., same frequency shift) may interferewith each other such that a PRS signal from a more distant TRP may beoverwhelmed by a PRS signal from a closer TRP such that the signal fromthe more distant TRP may not be detected. PRS muting may be used to helpreduce interference by muting some PRS signals (reducing the power ofthe PRS signal, e.g., to zero and thus not transmitting the PRS signal).In this way, a weaker (at the UE) PRS signal may be more easily detectedby the UE without a stronger PRS signal interfering with the weaker PRSsignal. The term RS, and variations thereof (e.g., PRS, SRS), may referto one reference signal or more than one reference signal.

Positioning reference signals (PRS) include downlink PRS (DL PRS, oftenreferred to simply as PRS) and uplink PRS (UL PRS) (which may be calledSRS (Sounding Reference Signal) for positioning). A PRS may be generatedusing a PN code (pseudorandom number code) (e.g., by modulating acarrier signal with the PN code) such that a source of the PRS may serveas a pseudo-satellite (a pseudolite). The PN code may be unique to thePRS source (at least within a specified area such that identical PRSfrom different PRS sources do not overlap). PRS may comprise PRSresources or PRS resource sets of a frequency layer. A DL PRSpositioning frequency layer (or simply a frequency layer) is acollection of DL PRS resource sets, from one or more TRPs, with PRSresource(s) that have common parameters configured by higher-layerparameters DL-PRS-PositioningFrequencyLayer, DL-PRS-ResourceSet, andDL-PRS-Resource. Each frequency layer has a DL PRS subcarrier spacing(SCS) for the DL PRS resource sets and the DL PRS resources in thefrequency layer. Each frequency layer has a DL PRS cyclic prefix (CP)for the DL PRS resource sets and the DL PRS resources in the frequencylayer. In 5G, a resource block occupies 12 consecutive subcarriers and aspecified number of symbols. Also, a DL PRS Point A parameter defines afrequency of a reference resource block (and the lowest subcarrier ofthe resource block), with DL PRS resources belonging to the same DL PRSresource set having the same Point A and all DL PRS resource setsbelonging to the same frequency layer having the same Point A. Afrequency layer also has the same DL PRS bandwidth, the same start PRB(and center frequency), and the same value of comb size (i.e., afrequency of PRS resource elements per symbol such that for comb-N,every N^(th) resource element is a PRS resource element). A PRS resourceset is identified by a PRS resource set ID and may be associated with aparticular TRP (identified by a cell ID) transmitted by an antenna panelof a base station. A PRS resource ID in a PRS resource set may beassociated with an omnidirectional signal, and/or with a single beam(and/or beam ID) transmitted from a single base station (where a basestation may transmit one or more beams). Each PRS resource of a PRSresource set may be transmitted on a different beam and as such, a PRSresource, or simply resource can also be referred to as a beam. Thisdoes not have any implications on whether the base stations and thebeams on which PRS are transmitted are known to the UE.

A TRP may be configured, e.g., by instructions received from a serverand/or by software in the TRP, to send DL PRS per a schedule. Accordingto the schedule, the TRP may send the DL PRS intermittently, e.g.,periodically at a consistent interval from an initial transmission. TheTRP may be configured to send one or more PRS resource sets. A resourceset is a collection of PRS resources across one TRP, with the resourceshaving the same periodicity, a common muting pattern configuration (ifany), and the same repetition factor across slots. Each of the PRSresource sets comprises multiple PRS resources, with each PRS resourcecomprising multiple Resource Elements (REs) that may be in multipleResource Blocks (RBs) within N (one or more) consecutive symbol(s)within a slot. An RB is a collection of REs spanning a quantity of oneor more consecutive symbols in the time domain and a quantity (12 for a5G RB) of consecutive sub-carriers in the frequency domain. Each PRSresource is configured with an RE offset, slot offset, a symbol offsetwithin a slot, and a number of consecutive symbols that the PRS resourcemay occupy within a slot. The RE offset defines the starting RE offsetof the first symbol within a DL PRS resource in frequency. The relativeRE offsets of the remaining symbols within a DL PRS resource are definedbased on the initial offset. The slot offset is the starting slot of theDL PRS resource with respect to a corresponding resource set slotoffset. The symbol offset determines the starting symbol of the DL PRSresource within the starting slot. Transmitted REs may repeat acrossslots, with each transmission being called a repetition such that theremay be multiple repetitions in a PRS resource. The DL PRS resources in aDL PRS resource set are associated with the same TRP and each DL PRSresource has a DL PRS resource ID. A DL PRS resource ID in a DL PRSresource set is associated with a single beam transmitted from a singleTRP (although a TRP may transmit one or more beams).

A PRS resource may also be defined by quasi-co-location and start PRBparameters. A quasi-co-location (QCL) parameter may define anyquasi-co-location information of the DL PRS resource with otherreference signals. The DL PRS may be configured to be QCL type D with aDL PRS or SS/PBCH (Synchronization Signal/Physical Broadcast Channel)Block from a serving cell or a non-serving cell. The DL PRS may beconfigured to be QCL type C with an SS/PBCH Block from a serving cell ora non-serving cell. The start PRB parameter defines the starting PRBindex of the DL PRS resource with respect to reference Point A. Thestarting PRB index has a granularity of one PRB and may have a minimumvalue of 0 and a maximum value of 2176 PRBs.

A PRS resource set is a collection of PRS resources with the sameperiodicity, same muting pattern configuration (if any), and the samerepetition factor across slots. Every time all repetitions of all PRSresources of the PRS resource set are configured to be transmitted isreferred as an “instance”. Therefore, an “instance” of a PRS resourceset is a specified number of repetitions for each PRS resource and aspecified number of PRS resources within the PRS resource set such thatonce the specified number of repetitions are transmitted for each of thespecified number of PRS resources, the instance is complete. An instancemay also be referred to as an “occasion.” A DL PRS configurationincluding a DL PRS transmission schedule may be provided to a UE tofacilitate (or even enable) the UE to measure the DL PRS.

Multiple frequency layers of PRS may be aggregated to provide aneffective bandwidth that is larger than any of the bandwidths of thelayers individually. Multiple frequency layers of component carriers(which may be consecutive and/or separate) and meeting criteria such asbeing quasi co-located (QCLed), and having the same antenna port, may bestitched to provide a larger effective PRS bandwidth (for DL PRS and ULPRS) resulting in increased time of arrival measurement accuracy.Stitching comprises combining PRS measurements over individual bandwidthfragments into a unified piece such that the stitched PRS may be treatedas having been taken from a single measurement. Being QCLed, thedifferent frequency layers behave similarly, enabling stitching of thePRS to yield the larger effective bandwidth. The larger effectivebandwidth, which may be referred to as the bandwidth of an aggregatedPRS or the frequency bandwidth of an aggregated PRS, provides for bettertime-domain resolution (e.g., of TDOA). An aggregated PRS includes acollection of PRS resources and each PRS resource of an aggregated PRSmay be called a PRS component, and each PRS component may be transmittedon different component carriers, bands, or frequency layers, or ondifferent portions of the same band.

RTT positioning is an active positioning technique in that RTT usespositioning signals sent by TRPs to UEs and by UEs (that areparticipating in RTT positioning) to TRPs. The TRPs may send DL-PRSsignals that are received by the UEs and the UEs may send SRS (SoundingReference Signal) signals that are received by multiple TRPs. A soundingreference signal may be referred to as an SRS or an SRS signal. In 5Gmulti-RTT, coordinated positioning may be used with the UE sending asingle UL-SRS for positioning that is received by multiple TRPs insteadof sending a separate UL-SRS for positioning for each TRP. A TRP thatparticipates in multi-RTT will typically search for UEs that arecurrently camped on that TRP (served UEs, with the TRP being a servingTRP) and also UEs that are camped on neighboring TRPs (neighbor UEs).Neighbor TRPs may be TRPs of a single BTS (e.g., gNB), or may be a TRPof one BTS and a TRP of a separate BTS. For RTT positioning, includingmulti-RTT positioning, the DL-PRS signal and the UL-SRS for positioningsignal in a PRS/SRS for positioning signal pair used to determine RTT(and thus used to determine range between the UE and the TRP) may occurclose in time to each other such that errors due to UE motion and/or UEclock drift and/or TRP clock drift are within acceptable limits. Forexample, signals in a PRS/SRS for positioning signal pair may betransmitted from the TRP and the UE, respectively, within about 10 ms ofeach other. With SRS for positioning signals being sent by UEs, and withPRS and SRS for positioning signals being conveyed close in time to eachother, it has been found that radio-frequency (RF) signal congestion mayresult (which may cause excessive noise, etc.) especially if many UEsattempt positioning concurrently and/or that computational congestionmay result at the TRPs that are trying to measure many UEs concurrently.

RTT positioning may be UE-based or UE-assisted. In UE-based RTT, the UE200 determines the RTT and corresponding range to each of the TRPs 300and the position of the UE 200 based on the ranges to the TRPs 300 andknown locations of the TRPs 300. In UE-assisted RTT, the UE 200 measurespositioning signals and provides measurement information to the TRP 300,and the TRP 300 determines the RTT and range. The TRP 300 providesranges to a location server, e.g., the server 400, and the serverdetermines the location of the UE 200, e.g., based on ranges todifferent TRPs 300. The RTT and/or range may be determined by the TRP300 that received the signal(s) from the UE 200, by this TRP 300 incombination with one or more other devices, e.g., one or more other TRPs300 and/or the server 400, or by one or more devices other than the TRP300 that received the signal(s) from the UE 200.

Various positioning techniques are supported in 5G NR. The NR nativepositioning methods supported in 5G NR include DL-only positioningmethods, UL-only positioning methods, and DL+UL positioning methods.Downlink-based positioning methods include DL-TDOA and DL-AoD.Uplink-based positioning methods include UL-TDOA and UL-AoA. CombinedDL+UL-based positioning methods include RTT with one base station andRTT with multiple base stations (multi-RTT).

A position estimate (e.g., for a UE) may be referred to by other names,such as a location estimate, location, position, position fix, fix, orthe like. A position estimate may be geodetic and comprise coordinates(e.g., latitude, longitude, and possibly altitude) or may be civic andcomprise a street address, postal address, or some other verbaldescription of a location. A position estimate may further be definedrelative to some other known location or defined in absolute terms(e.g., using latitude, longitude, and possibly altitude). A positionestimate may include an expected error or uncertainty (e.g., byincluding an area or volume within which the location is expected to beincluded with some specified or default level of confidence).

Carrier-Phase-Based Positioning

A GNSS receiver may measure satellite vehicle signals (SV signals) todetermine a location of the GNSS receiver. For example, a UE may measuretimes of arrival of codes in SV signals and estimate a location, orprovide measurement information to another device such as a locationserver that estimates a location, of the UE using the times of arrival.The location of the UE may be more-accurately determined usingcarrier-phase measurements of the SV signals and one or more positioningtechniques such as RTK or PPP.

Referring to FIG. 5 , with further reference to FIGS. 1-4 , a UE 500includes a processor 510, an interface 520, and a memory 530communicatively coupled to each other by a bus 540. The UE 500 mayinclude some or all of the components shown in FIG. 5 , and may includeone or more other components such as any of those shown in FIG. 2 suchthat the UE 200 may be an example of the UE 500. The processor 510 mayinclude one or more components of the processor 210. The interface 520may include one or more of the components of the transceiver 215, e.g.,the wireless transmitter 242 and the antenna 246, or the wirelessreceiver 244 and the antenna 246, or the wireless transmitter 242, thewireless receiver 244, and the antenna 246. Also or alternatively, theinterface 520 may include the wired transmitter 252 and/or the wiredreceiver 254. The interface 520 may include the SPS receiver 217 and theSPS antenna 262. The memory 530 may be configured similarly to thememory 211, e.g., including software with processor-readableinstructions configured to cause the processor 510 to perform functions.

The description herein may refer to the processor 510 performing afunction, but this includes other implementations such as where theprocessor 510 executes software (stored in the memory 530) and/orfirmware. The description herein may refer to the UE 500 performing afunction as shorthand for one or more appropriate components (e.g., theprocessor 510 and the memory 530) of the UE 500 performing the function.The processor 510 (possibly in conjunction with the memory 530 and, asappropriate, the interface 520) includes a carrier phase unit 550. Theconfiguration and functionality of the carrier phase unit 550 isdiscussed further herein, with the carrier phase unit 550 beingconfigured to perform the functionality described as being performed bythe carrier phase unit 550.

Referring also to FIG. 6 , code-phase measurements and carrier-phasemeasurements may be used to determine location of a target UE with highprecision. A carrier signal 610 is produced by a satellite, e.g., the SV190 (FIG. 1 ). The carrier signal 610 (also called a carrier wave or acarrier) is a waveform used for modulation with a modulation signal toproduce a new signal. Here, a PRN code signal 620 (pseudorandom noisecode signal) is used by the SV 190 to modulate the carrier signal 610 toproduce an SV signal 630 (satellite vehicle signal), which comprises thePRN code signal 620 and the carrier signal 610.

Referring also to FIG. 7 , the SV 190 transmits the SV signal 630 to aGNSS receiver 700 (e.g., the UE 200), although only the carrier signal610 of the SV signal 630 is shown in FIG. 7 . The GNSS receiver 700(e.g., the processor 510) can correlate the PRN code signal 620 with astored PRN code corresponding to the SV 190 to determine a time ofarrival of the PRN code signal 620. The GNSS receiver 700 can use thetime of arrival to determine a time of travel between the SV 190 and theGNSS receiver 700 to determine a distance between the SV 190 and theGNSS receiver 700. The distance determined using the PRN code signal 620typically has an error of at least several meters (e.g., 5m, 10m, ormore). If, however, the GNSS receiver 700 can determine the totalcarrier phase of the carrier signal 610 (i.e., the number of fullcarrier signal cycles plus the fractional carrier phase) between the SV190 and the GNSS receiver 700, then the GNSS receiver can determine thedistance between the SV 190 and the GNSS receiver 700 much moreaccurately, e.g., within centimeters. The GNSS receiver 700, e.g., thecarrier phase unit 550, can measure the instantaneous phase of thecarrier signal 610 at the GNSS receiver 700, and use this measuredphased to determine the fractional phase of the carrier signal 610between the SV 190 and the GNSS receiver 700. The GNSS receiver 700cannot measure the total phase of the carrier signal 610 between the SV190 and the GNSS receiver 700, but can use one or more known techniquesto determine the unknown number of full cycles of the carrier signal 610between the SV 190 and the GNSS receiver 700. The unknown integer numberof full cycles of the carrier signal 610 between the SV 190 and the GNSSreceiver 700 is referred to as the GNSS integer ambiguity. Examples oftechniques for solving the integer ambiguity include searching throughpossible integer solutions and choosing the solution with the lowestresiduals, using carrier phase measurements from multiple epochs andsatellite geometry (e.g., multiple satellite constellations) to estimatethe GNSS receiver location, or averaging multiple independentmeasurements to an estimated position with the lowest noise level.

For carrier-phase-based positioning, a range (distance) from a source ofa carrier signal to a receiver of the carrier signal is determined asthe total carrier phase (the number of cycles, including a partial cycle(if any)) between the source and receiver multiplied by the wavelength,λ, of the carrier signal. The total carrier phase can be represented asan integer number N of full cycles between the source and receiver plusa fractional carrier phase θ divided by 2n. The fractional carrier phaseθ is given by

θ=θ(t)−θ₀  (1)

where θ₀ is the initial carrier phase at the transmitter (carrier signalsource) and θ(t) is the carrier phase measured at the receiver. Thus,the range ρ may be given by

$\begin{matrix}{\rho = {\left( {N + \frac{{\theta(t)} - \theta_{0}}{2\pi}} \right)*\lambda}} & (2)\end{matrix}$

The initial phase component can be removed from consideration byemploying a double-difference technique using a reference node tomeasure the same satellite signal as measured by the GNSS receiver. Therange may thus be determined based on the measured phase anddetermination of the integer number of cycles of the carrier signal 610between the source (e.g., the SV 190) and the GNSS receiver 700.

Based on the distance between the SV 190 and the GNSS receiver 700determined using the PRN code signal 620, the number of full cycles ofthe carrier signal 610 may be narrowed to a range 720 of possiblenumbers of full cycles. To determine the total carrier phase between theSV 190 and the GNSS receiver 700, the GNSS receiver 700 can use thedistance determined using the PRN code signal 620 to set a searchregion, referred to as the GNSS integer ambiguity search space, for analgorithm to determine the integer number of carrier signal cyclesbetween the SV 190 and the GNSS receiver 700. Determining a search spacehelps simplify the determination of the number of full cycles of thecarrier signal 610, and helps the GNSS receiver 700 be able to determinethe integer solution. If the GNSS receiver 700 can reduce the size ofthe search space (i.e., the length of the range 720) for the actualinteger number of cycles to the GNSS receiver 700, then the time tosolve the integer ambiguity may be decreased, and/or a solution to theinteger ambiguity may be determined under conditions (e.g., SV signalmultipath such as in urban canyons) in which a solution may not bepossible absent reduction of the search space.

Referring also to FIG. 8 , the distance determined by correlating thePRN code, and an uncertainty in this distance, can be used to determinea minimum range 810 from the SV 190 to the GNSS receiver and a maximumrange 820 from the SV 190 to the GNSS receiver 700. The range 720corresponds to the difference between the maximum range 820 and theminimum range 810 and spans several cycles of the carrier signal 610indicated by a scale 840. A two-dimensional position error ellipse 830defines the minimum range 810 and the maximum range 820. Thetwo-dimensional position error ellipse 830 is the projection of athree-dimensional position error ellipsoid of the position of the GNSSreceiver 700 based on GNSS signals (although error volumes of shapesother than ellipsoids (e.g., irregular shapes) and/or two-dimensionalprojections of shapes other than ellipses may be used). The projectionof the two-dimensional position error ellipse 830 onto the satelliteline of sight to the GNSS receiver 700 (e.g., the line of the maximumrange 820) yields the range 720, the length of which is the searchspace.

Referring also to FIG. 9 , a spatial uncertainty of a location of theGNSS receiver 700 relative to a terrestrial base station 910 may bedetermined. For example, the base station 910, e.g., the TRP 300, maytransfer one or more signals (e.g., PRS) with the GNSS receiver 700(e.g., transmit one or more signals to the GNSS receiver 700 and/orreceive one or more signals from the GNSS receiver 700) to determine arange and range uncertainty relative to the base station 910. Forexample, the signal transfer may be used to determine a round-trip time(RTT) for the base station 910 and the GNSS receiver 700, and an RTTuncertainty. An annulus 920 corresponds to the RTT and the RTTuncertainty, with a width 930 of the annulus 920 being dependent on theRTT uncertainty. The GNSS receiver 700, e.g., the carrier phase unit550, can bound the integer ambiguity search space by the spatial boundsof the GNSS receiver location determined by signal transfer between thebase station 910 and the GNSS receiver 700, here a distance measurecorresponding to the RTT and a distance uncertainty corresponding to theRTT uncertainty. Thus, in this example, the carrier phase unit 550bounds the integer ambiguity of the two-dimensional position errorellipse 830 by boundary of the annulus 920. The carrier phase unit 550determines a reduced two-dimensional position error ellipse 940 based onthe intersection of the two-dimensional position error ellipse 830 andthe annulus 920. The carrier phase unit 550 determines an ellipticalshape (e.g., the largest ellipse or the largest ellipsoid) that fitswithin the intersection of the two-dimensional position error ellipse830 and the annulus 920 and sets this as the reduced two-dimensionalposition error ellipse 940, which has a smaller search space (projectiononto the satellite line of sight). The base station 910 may be any of avariety of base stations, employing one or more signaling technologies,such that the spatial uncertainty that can be determined by signaltransfer with the base station 910 is small enough to be able to limitthe size of the error ellipse 830. For example, the base station 910 maybe configured to transfer 5G NR PRS with the GNSS receiver 700. Asanother example, the base station 910 may be a WiFi base stationconfigured to perform signal transfer according to the IEEE 802.11mcprotocol for determining RTT.

Referring also to FIG. 10 , an angular spatial uncertainty of thelocation of the GNSS receiver 700 relative to a terrestrial base station1010 may be used to bound an error ellipse and thus an integer ambiguitysearch space. For example, the GNSS receiver 700 may transmit PRS 1020to the terrestrial base station 1010 and the terrestrial base station1010 can measure the PRS 1020 and determine an angle of arrival (AoA) ofthe PRS 1020 and an AoA uncertainty 1030 corresponding to the determinedAoA. The carrier phase unit 550 may bound the error ellipse 830 by thespatial uncertainty corresponding to the AoA and AoA uncertainty todetermine a reduced error ellipse 1040 with a correspondingly smallersearch space than the error ellipse 830.

Referring also to FIG. 11 , a location estimate and correspondinglocation uncertainty may be used to bound an error ellipse and thus theinteger ambiguity search space. For example, the GNSS receiver 700 maytransfer signals with multiple base stations (not shown) such thatranges to the base stations may be determined, and triangulation used todetermine a location estimate and corresponding location uncertainty,from which a location error region, here a location error ellipse 1100may be determined. The carrier phase unit 550 may bound the errorellipse 830 with the location error ellipse 1100 to determine a reducederror ellipse 1140 with a correspondingly smaller search space than theerror ellipse 830.

Referring also to FIGS. 12 and 13 , combinations of spatialuncertainties, e.g., one or more locations and corresponding locationuncertainty(ies), one or more angles and corresponding angleuncertainty(ies), and/or one or more ranges and corresponding rangeuncertainty(ies) may be used to bound a position error ellipse todetermine an integrated error space. As shown in FIG. 12 , the range andrange uncertainty shown in FIG. 9 is combined with the angle and angleuncertainty shown in FIG. 10 to constrain the error ellipse 830 withinan intersection region 1210 (i.e., the intersection of the annulus 920and the angle uncertainty 1030). The carrier phase unit 550 mayconstrain reduce the error ellipse 830 to a reduced error ellipse 1200(an integrated error space) the projection of which onto satellite lineof sight provides a reduced search space compared to the projection ofthe error ellipse 830 onto satellite line of sight. Here, the errorellipse 1200 is a largest ellipse that fits within the intersectionregion 1210. As shown in FIG. 13 , a first annulus 1310 corresponding toa first range and first range uncertainty, a second annulus 1320corresponding to a second range and second range uncertainty, and anangle and angle uncertainty 1330 intersect over an intersection region1350. The intersection region 1350 may be used to reduce the size of theerror ellipse 830 to a reduced error ellipse 1340 with a correspondingreduced integer ambiguity search space. Here, the error ellipse 1340 isthe largest ellipse that fits within the intersection region 1350.

The carrier phase unit 550 may determine an integrated error space basedon an intersection of an error ellipse based on correlation of the PRNcode signal 620 and one or more spatial constraints determined fromsignal transfer with one or more terrestrial base stations (e.g.,position estimate(s), angle(s) relative to the base station(s), range(s)relative to the base station(s)). The carrier phase unit 550 maydetermine the largest ellipse that will fit within the intersection asan integrated error space, with the projection of this ellipse ontosatellite line of sight yielding the search space.

The GNSS receiver 700, e.g., the processor 510, may use a reducedinteger ambiguity search window to find the integer number of carrierphase cycles between the SV 190 and the GNSS receiver 700. The reducedinteger ambiguity search window will typically be smaller than the range720 corresponding to the error ellipse 830 determined from theuncertainty of the correlation of the PRN code signal 620 alone. Thus,the speed at which the carrier phase unit 550 solves the integerambiguity will be faster than without spatially constraining the errorellipse 830, and/or the carrier phase unit 550 may be able to solve theinteger ambiguity under conditions where solving the integer ambiguityis not possible (at least not to a threshold level of convergence and/orwithin a threshold amount of acceptable time). Solution of the integerambiguity may not be possible, without reduction of the error ellipse830, e.g., due to a very large error ellipse 830 (e.g., under multipathconditions such as an urban canyon).

The GNSS receiver 700 can use the integer number of carrier cyclesbetween the SV 190 and the GNSS receiver 700 to determine the positionof the GNSS receiver 700. For example, the processor 510 may determinethe total carrier phase between the SV 190 and the UE 500, and determinethe range (to a high degree of accuracy, e.g., within centimeters)between the SV 190 and the UE 500. The processor 510 may use this range,and ranges to other satellites and/or ranges to one or more terrestrialbase stations (e.g., if an insufficient quantity of ranges to satellitesis known for a position estimate of the UE 500) to determine a positionestimate for the UE 500 for mobile-based positioning. Also oralternatively, for mobile-assisted positioning, the UE 500 may provideposition information (e.g., raw measurement(s) and/or processedmeasurement information (e.g., range(s)) to another device, such as alocation server, for determination of the position estimate.

Referring to FIG. 14 , with further reference to FIGS. 1-13 , asignaling and process flow 1400 for measuring carrier phase, anddetermining position information based on carrier phase measurements,includes the stages shown. In the flow 1400, signals are transferredbetween the SV 190, the UE 500 (e.g., an example of the GNSS receiver700), one or more base stations 1401, and a positioning entity 1402. Thepositioning entity 1402 may be a standalone entity or a part of anentity (e.g., a UE, a TRP, a server).

At stage 1410, a location of the UE 500 is requested and a preliminaryinteger ambiguity search space determined for resolving a carrier signalinteger ambiguity. As sub-stage 1412, the UE 500 requests a GNSS fix.The request may be initiated internally, e.g., an application requestinga location of the UE 500. The request may be initiated externally, e.g.,a location services (LCS) client requesting location of the UE 500 andthe LCS (e.g., in the server 400) sending a request to the UE 500. TheSV 190 sends an SV signal 1414 that the UE 500 receives (e.g., by theinterface 520 such as the SPS antenna 262 and the SPS receiver 217). Atsub-stage 1416, the UE 500, e.g., the carrier phase unit 550, determinesa code-phase-based integer ambiguity search space. For example, the UE500 correlates a PRN code with the SV signal 630 to determine anapproximate location of the UE 500 and an integer ambiguity searchspace, e.g., the range 720 corresponding to the error ellipse 830, forresolving the integer number of cycles of the carrier signal 610 betweenthe SV 190 and the UE 500.

At stage 1420, the UE 500 obtains spatial information regarding locationof the UE 500 based on terrestrial-based signaling. The UE 500 may senda position information request 1421 to the base station(s) 1401 forposition information (e.g., one or more position measurements, one ormore ranges between base station and the UE 500, one or more angles ofthe UE 500 relative to one or more base stations, etc.). The basestation(s) 1401 may respond by sending position information 1425 to theUE 500 if the position information is already known. Also oralternatively, the base station(s) 1401 may perform operations totransfer PRS with the UE 500 (e.g., transmit PRS to the UE 500 and/orreceive PRS from the UE 500) from which position information can bedetermined. For example, at sub-stage 1422, the base station(s) 1401negotiate with the server 400 to determine one or more PRS schedules forPRS transfer between the base station(s) 1401 and the UE 500. The basestation(s) 1401 transmit the PRS configuration(s) 1423 to the UE 500.The UE 500 and the base station(s) 1401 transfer PRS 1424 (e.g.,bidirectionally, e.g., to determine RTT, or unidirectionally, e.g., todetermine AoA at the base station(s) 1401). The base station(s) 1401 maydetermine position information such as range to the UE 500 andcorresponding range uncertainty, angle to the UE and angle uncertainty,position estimate for the UE 500 and position uncertainty. The basestation(s) 1401 transmit the position information 1425 to the UE 500.Also or alternatively, at sub-stage 1426 the carrier phase unit 550 maydetermine position information (e.g., PRS measurement(s), range(s),position estimate(s)) from one or more PRS received by the UE 500. Alsoor alternatively, at sub-stage 1426 the carrier phase unit 550 mayretrieve position information from the memory 530 if positioninformation has previously been obtained and stored in the memory 530.The transfer of PRS is an example and not required. For example, thebase station(s) 1401 may include one or more WiFi base stations (e.g.,IEEE 802.11mc base station(s)) with which the UE 500 may transfersignals to determine position information, e.g., RTT from which range(s)and range uncertainty(ies) may be determined.

At stage 1430, the carrier phase unit 550 determines the total carrierphase of the carrier signal 610 from the SV 190 to the UE 500. Atsub-stage 1432, the carrier phase unit 550 uses the position informationobtained at stage 1420 to constrain the error ellipse 830 to a reducederror ellipse with a corresponding reduced search space and uses thereduced search space to determine a solution to the integer ambiguity.While in the flow 1400, the error ellipse 830 is determined and thenreduced based on the position information, this order is an example andnot a required order. For example, position information based onterrestrial signaling may be determined and used to constrain thedetermination of an error ellipse based on correlation to the PRN codesignal 620. The size of the satellite positioning system carrier phaseinteger ambiguity search space may be constrained based on spatialinformation determined using multiple techniques and/or using signaltransfer with multiple base stations. For example, the search space maybe limited using range uncertainty from a base station to the apparatusand angular uncertainty of the apparatus relative to the base station.As another example, the search space may be limited using rangeuncertainties from multiple base stations to the apparatus. As anotherexample, the search space may be limited using angular uncertainties ofthe apparatus relative to multiple base stations. The search space maybe limited using one or more range uncertainties from one or more basestations to the apparatus and/or one or more angular uncertainties ofthe apparatus relative to one or more base stations. The SV 190transmits an SV signal 1434 to the UE 500 that the carrier phase unit550 measures. At sub-stage 1436, the carrier phase unit 550 determinesthe total carrier phase of the SV signal 1434 from the SV 190 to the UE500 using the reduced integer ambiguity search space to solve theinteger ambiguity and using the measured carrier phase and a knowntechnique (e.g., double differencing) to determine the fractionalcarrier phase. Using the reduced integer ambiguity search space mayspeed the convergence of the integer ambiguity solution, speeding thedetermination of a range between the SV 190 and the UE 500, and/orenabling convergence of the integer ambiguity solution under conditionswhere convergence would not occur without constraint of the errorellipse 830.

At stage 1440, the UE 500 determines position information based on thedetermined carrier phase. The position information may be the determinedcarrier phase, or information derived from the determined carrier phasesuch as range to the SV 190. The flow 1400 may be repeated for one ormore other satellites to obtain carrier phase information for multiplesatellites and thus ranges to multiple satellites. The UE 500 may usethe ranges to the satellites to determine a position of the UE 500 if asufficient number of ranges are determined, or the UE 500 may combinethe range(s) to the satellite(s) with other position information (e.g.,one or more ranges to one or more terrestrial base stations, one or moreangles relative to one or more terrestrial base stations, etc.) todetermine a position estimate for the UE 500. The UE 500 may transmitposition information 1442 to the positioning entity 1402.

At stage 1450, the positioning entity 1402 determines positioninformation for the UE 500 (e.g., a position estimate) based theposition information 1442 (e.g., measurements, total carrier phase toeach of one or more satellites, etc.). The positioning entity 1402 maycombine multiple pieces of position information, e.g., measurementsand/or ranges, to determine further position information, e.g., aposition estimate. The positioning entity 1402 may provide positioninformation determined by the positioning entity 1402 to one or moreother entities, e.g., the server 400, the UE 500, etc.

Referring to FIG. 15 , with further reference to FIGS. 1-14 , a method1500 of determining an integer ambiguity search space includes thestages shown. The method 1500 is, however, an example only and notlimiting. The method 1500 may be altered, e.g., by having stages added,removed, rearranged, combined, performed concurrently, and/or havingsingle stages split into multiple stages.

At stage 1510, the method 1500 includes obtaining, at an apparatus, acode phase measurement of a satellite vehicle signal comprising apseudorandom noise code and a carrier signal. For example, the UE 500receives the SV signal 1414 (e.g., the SV signal 630 including the PRNcode signal 620) at stage 1410. The processor 510, possibly includingthe memory 530, in combination with the interface 520 (e.g., the SPSreceiver 217 and the SPS antenna 262) may comprise means for obtainingthe code phase measurement.

At stage 1520, the method 1500 includes obtaining, at the apparatus,spatial information corresponding to a wireless terrestrial signaltransferred between the apparatus and a terrestrial base station. Forexample, the UE 500 receives the position information 1425 from the basestation 1401, retrieves position information from the memory 530, and/ordetermines position information at sub-stage 1432 based on spatialinformation determined from one or more signals (e.g., PRS) transferredbetween the UE 500 and the base station(s) 1401, e.g., at stage 1420.The processor 510, possibly in combination with the memory 530, possiblyin combination with the interface 520 (e.g., the wireless transmitter242 and the antenna 246 and/or the wireless receiver 244 and the antenna246) may comprise means for obtaining the spatial information.

At stage 1530, the method 1500 includes determining, at the apparatus, asatellite positioning system carrier phase integer ambiguity searchspace based on the code phase measurement. For example, the carrierphase unit 550 may determine the error ellipse 830 based on a range andrange uncertainty determined from measuring the PRN code signal 620 anddetermine the range 720 of the search space based on the error ellipse830. The processor 510, possibly in combination with the memory 530, maycomprise means for determining the satellite positioning system carrierphase integer ambiguity search space.

At stage 1540, the method 1500 includes constraining a size of thesatellite positioning system carrier phase integer ambiguity searchspace based on the spatial information. For example, the carrier phaseunit 550 may determine an intersection of the error ellipse 830 andspatial information such as one or more ranges and corresponding rangeuncertainty(ies) of the UE 500 relative to one or more base stations,one or more angles and corresponding angle uncertainty(ies) of the UE500 relative to one or more base stations, and/or a position estimateand position uncertainty for the UE 500 based on terrestrial signaltransfer. The carrier phase unit 550 may determine the error ellipse 830and then limit the size of an error ellipse based on the spatialinformation, or the carrier phase unit 550 may constrain determinationof the error ellipse 830 based on the spatial information. The carrierphase unit 550 may determine an integer ambiguity search space based onthe constrained error ellipse, e.g., by projecting the constrained errorellipse onto a line of sight of a satellite. Thus, constraining theerror ellipse constrains the integer ambiguity search space. Theprocessor 510, possibly in combination with the memory 530, may comprisemeans for determining the constraining a size of the satellitepositioning system carrier phase integer ambiguity search space.Constraining the size of the satellite positioning system carrier phaseinteger ambiguity search space may speed the convergence of a solutionfor the integer ambiguity, thus improving positioning speed and reducinglatency. Also or alternatively, constraining the size of the satellitepositioning system carrier phase integer ambiguity search space mayenable convergence of the integer ambiguity solution under conditionswhere convergence would not occur (e.g., at all or within an acceptableamount of time) absent the constraint on the size of the integerambiguity search space.

Implementations of the method 1500 may include one or more of thefollowing features. In an example implementation, the spatialinformation comprises a range uncertainty of a location of the apparatusrelative to the terrestrial base station. For example, the spatialinformation may comprise an annulus, such as the annulus 920, or athree-dimensional range uncertainty (e.g., a spherical shell or aportion thereof, a spherical shell being a generalization of an annulusto three dimensions and comprising a region between two concentricspheres). In a further example implementation, the method 1500 includes:transmitting a first positioning reference signal to the terrestrialbase station; measuring a second positioning reference signal receivedfrom the terrestrial base station; and obtaining a round trip timeuncertainty corresponding to the first positioning reference signal andthe second positioning reference signal as the range uncertainty. Forexample, the UE 500 and the base station 1401 transfer the PRS 1424,measure the PRS 1424, and determine an RTT between the UE 500 and thebase station 1401. Either the base station 1401, or the UE 500, oranother entity (e.g., the server 400) may determine the RTT. The RTT maybe provided to the UE 500 from another entity that determines the RTT.The processor 510, possibly in combination with the memory 530, incombination with the interface 520 (e.g., the wireless transmitter 242and the antenna 246) may comprise means for transmitting the first PRS.The processor 510, possibly in combination with the memory 530, incombination with the interface 520 (e.g., the wireless receiver 242 andthe antenna 246) may comprise means for measuring the second PRS. Theprocessor 510, possibly in combination with the memory 530, possibly incombination with the interface 520 (e.g., the wireless receiver 244 andthe antenna 246) may comprise means for obtaining the RTT. In anotherfurther example implementation, the range uncertainty is less than twometers. For example, 5G NR positioning (or more accurateterrestrial-based positioning) is used to determine the spatialinformation to provide a range uncertainty of less than two meters tohelp reduce the integer ambiguity search space. In another furtherexample implementation, the spatial information comprises a plurality ofrange uncertainties of the apparatus relative to a plurality ofterrestrial base stations. For example, as shown in FIG. 13 , multiplerange uncertainties relative to multiple reference points, e.g., basestations, may be used to determine (e.g., constrain) a integer ambiguitysearch space.

Also to alternatively, implementations of the method 1500 may includeone or more of the following features. In an example implementation, thespatial information comprises an angular uncertainty of a location ofthe apparatus relative to the terrestrial base station. For example, thespatial information that may be used to constrain the size of theinteger ambiguity search space is an angular uncertainty such as the AoAuncertainty 1030 or the angle uncertainty 1330 that can be used alone orin combination with other spatial information to constrain an integerambiguity search space (e.g., by constraining an error ellipse). In afurther example implementation, the spatial information comprises aplurality of angular uncertainties of the location of the apparatusrelative to a plurality of terrestrial base stations. In another furtherexample implementation, the spatial information comprises a rangeuncertainty of the location of the apparatus relative to the terrestrialbase station. For example, as shown in FIG. 13 , both range/rangeuncertainty and angle/angle uncertainty can be used to determine aninteger ambiguity search space. In another example implementation,determining the satellite positioning system carrier phase integerambiguity search space comprises determining an intersection region, theintersection region being an intersection of an unconstrained satellitepositioning system error space based on the code phase measurement andan uncertainty region of a location of the apparatus corresponding tothe spatial information. For example, the carrier phase unit 550 maydetermine the intersection of the error ellipse 830 and one or moreposition/position uncertainty combinations. The intersection may furtherbe an intersection with one or more angle/angle uncertainty combinationsand/or one or more range/range uncertainty combinations. In a furtherexample implementation, determining the satellite positioning systemcarrier phase integer ambiguity search space comprises determining thesatellite positioning system carrier phase integer ambiguity searchspace based on a largest ellipse that fits within the intersectionregion. The intersection may be a many sided, irregularly-shaped region,and the carrier phase unit 550 may determine the integer ambiguitysearch space as the satellite line-of-sight projection of the largestellipse that fits within the intersection region, e.g., the intersectionregion 1210 or the intersection region 1350.

Implementation Examples

Implementation examples are provided in the following numbered clauses.

Clause 1. An apparatus comprising:

a receiver;

a memory; and

a processor communicatively coupled to the receiver and the memory andconfigured to:

-   -   obtain a code phase measurement of a satellite vehicle signal        received via the receiver, the satellite vehicle signal        comprising a pseudorandom noise code and a carrier signal;    -   obtain spatial information corresponding to a wireless        terrestrial signal transferred between the apparatus and a        terrestrial base station; and    -   determine a satellite positioning system carrier phase integer        ambiguity search space based on the code phase measurement;

wherein the processor is configured to constrain a size of the satellitepositioning system carrier phase integer ambiguity search space based onthe spatial information.

Clause 2. The apparatus of clause 1, wherein the spatial informationcomprises a range uncertainty of a location of the apparatus relative tothe terrestrial base station.

Clause 3. The apparatus of clause 2, further comprising a transceiverthan includes the receiver, and wherein the processor is configured to:

transmit a first positioning reference signal to the terrestrial basestation;

measure a second positioning reference signal received from theterrestrial base station via the receiver; and

obtain a round trip time uncertainty corresponding to the firstpositioning reference signal and the second positioning reference signalas the range uncertainty.

Clause 4. The apparatus of clause 2, wherein the range uncertainty isless than two meters.

Clause 5. The apparatus of clause 2, wherein the spatial informationcomprises a plurality of range uncertainties of the apparatus relativeto a plurality of terrestrial base stations.

Clause 6. The apparatus of clause 1, wherein the spatial informationcomprises an angular uncertainty of a location of the apparatus relativeto the terrestrial base station.

Clause 7. The apparatus of clause 6, wherein the spatial informationcomprises a plurality of angular uncertainties of the location of theapparatus relative to a plurality of terrestrial base stations.

Clause 8. The apparatus of clause 6, wherein the spatial informationcomprises a range uncertainty of the location of the apparatus relativeto the terrestrial base station.

Clause 9. The apparatus of clause 1, wherein to determine the satellitepositioning system carrier phase integer ambiguity search space theprocessor is configured to determine an intersection region, theintersection region being an intersection of an unconstrained satellitepositioning system error space based on the code phase measurement andan uncertainty region of a location of the apparatus corresponding tothe spatial information.

Clause 10. The apparatus of clause 9, wherein the processor isconfigured to determine the satellite positioning system carrier phaseinteger ambiguity search space based on a largest ellipse that fitswithin the intersection region.

Clause 11. A method of determining an integer ambiguity search space,the method comprising:

obtaining, at an apparatus, a code phase measurement of a satellitevehicle signal comprising a pseudorandom noise code and a carriersignal;

obtaining, at the apparatus, spatial information corresponding to awireless terrestrial signal transferred between the apparatus and aterrestrial base station;

determining, at the apparatus, a satellite positioning system carrierphase integer ambiguity search space based on the code phasemeasurement; and

constraining a size of the satellite positioning system carrier phaseinteger ambiguity search space based on the spatial information.

Clause 12. The method of clause 11, wherein the spatial informationcomprises a range uncertainty of a location of the apparatus relative tothe terrestrial base station.

Clause 13. The method of clause 12, further comprising:

transmitting a first positioning reference signal to the terrestrialbase station;

measuring a second positioning reference signal received from theterrestrial base station; and

obtaining a round trip time uncertainty corresponding to the firstpositioning reference signal and the second positioning reference signalas the range uncertainty.

Clause 14. The method of clause 12, wherein the range uncertainty isless than two meters.

Clause 15. The method of clause 12, wherein the spatial informationcomprises a plurality of range uncertainties of the apparatus relativeto a plurality of terrestrial base stations.

Clause 16. The method of clause 11, wherein the spatial informationcomprises an angular uncertainty of a location of the apparatus relativeto the terrestrial base station.

Clause 17. The method of clause 16, wherein the spatial informationcomprises a plurality of angular uncertainties of the location of theapparatus relative to a plurality of terrestrial base stations.

Clause 18. The method of clause 16, wherein the spatial informationcomprises a range uncertainty of the location of the apparatus relativeto the terrestrial base station.

Clause 19. The method of clause 11, wherein determining the satellitepositioning system carrier phase integer ambiguity search spacecomprises determining an intersection region, the intersection regionbeing an intersection of an unconstrained satellite positioning systemerror space based on the code phase measurement and an uncertaintyregion of a location of the apparatus corresponding to the spatialinformation.

Clause 20. The method of clause 19, wherein determining the satellitepositioning system carrier phase integer ambiguity search spacecomprises determining the satellite positioning system carrier phaseinteger ambiguity search space based on a largest ellipse that fitswithin the intersection region.

Clause 21. An apparatus comprising:

means for obtaining a code phase measurement of a satellite vehiclesignal comprising a pseudorandom noise code and a carrier signal;

means for obtaining spatial information corresponding to a wirelessterrestrial signal transferred between the apparatus and a terrestrialbase station;

means for determining a satellite positioning system carrier phaseinteger ambiguity search space based on the code phase measurement; and

means for constraining a size of the satellite positioning systemcarrier phase integer ambiguity search space based on the spatialinformation.

Clause 22. The apparatus of clause 21, wherein the spatial informationcomprises a range uncertainty of a location of the apparatus relative tothe terrestrial base station.

Clause 23. The apparatus of clause 22, further comprising:

means for transmitting a first positioning reference signal to theterrestrial base station;

means for measuring a second positioning reference signal received fromthe terrestrial base station; and

means for obtaining a round trip time uncertainty corresponding to thefirst positioning reference signal and the second positioning referencesignal as the range uncertainty.

Clause 24. The apparatus of clause 22, wherein the range uncertainty isless than two meters.

Clause 25. The apparatus of clause 22, wherein the spatial informationcomprises a plurality of range uncertainties of the apparatus relativeto a plurality of terrestrial base stations.

Clause 26. The apparatus of clause 21, wherein the spatial informationcomprises an angular uncertainty of a location of the apparatus relativeto the terrestrial base station.

Clause 27. The apparatus of clause 26, wherein the spatial informationcomprises a plurality of angular uncertainties of the location of theapparatus relative to a plurality of terrestrial base stations.

Clause 28. The apparatus of clause 26, wherein the spatial informationcomprises a range uncertainty of the location of the apparatus relativeto the terrestrial base station.

Clause 29. The apparatus of clause 21, wherein the means for determiningthe satellite positioning system carrier phase integer ambiguity searchspace comprise means for determining an intersection region, theintersection region being an intersection of an unconstrained satellitepositioning system error space based on the code phase measurement andan uncertainty region of a location of the apparatus corresponding tothe spatial information.

Clause 30. The apparatus of clause 29, wherein the means for determiningthe satellite positioning system carrier phase integer ambiguity searchspace comprise means for determining the satellite positioning systemcarrier phase integer ambiguity search space based on a largest ellipsethat fits within the intersection region.

Clause 31. A non-transitory, processor-readable storage mediumcomprising processor-readable instructions to cause a processor, of anapparatus, to:

obtain a code phase measurement of a satellite vehicle signal comprisinga pseudorandom noise code and a carrier signal;

obtain spatial information corresponding to a wireless terrestrialsignal transferred between the apparatus and a terrestrial base station;

determine a satellite positioning system carrier phase integer ambiguitysearch space based on the code phase measurement; and

constrain a size of the satellite positioning system carrier phaseinteger ambiguity search space based on the spatial information.

Clause 32. The storage medium of clause 31, wherein the spatialinformation comprises a range uncertainty of a location of the apparatusrelative to the terrestrial base station.

Clause 33. The storage medium of clause 32, further comprisingprocessor-readable instructions to cause the processor to:

transmit a first positioning reference signal to the terrestrial basestation;

measure a second positioning reference signal received from theterrestrial base station; and

obtain a round trip time uncertainty corresponding to the firstpositioning reference signal and the second positioning reference signalas the range uncertainty.

Clause 34. The storage medium of clause 32, wherein the rangeuncertainty is less than two meters.

Clause 35. The storage medium of clause 32, wherein the spatialinformation comprises a plurality of range uncertainties of theapparatus relative to a plurality of terrestrial base stations.

Clause 36. The storage medium of clause 31, wherein the spatialinformation comprises an angular uncertainty of a location of theapparatus relative to the terrestrial base station.

Clause 37. The storage medium of clause 36, wherein the spatialinformation comprises a plurality of angular uncertainties of thelocation of the apparatus relative to a plurality of terrestrial basestations.

Clause 38. The storage medium of clause 36, wherein the spatialinformation comprises a range uncertainty of the location of theapparatus relative to the terrestrial base station.

Clause 39. The storage medium of clause 31, wherein theprocessor-readable instructions to cause the processor to determine thesatellite positioning system carrier phase integer ambiguity searchspace comprise processor-readable instructions to cause the processor todetermine an intersection region, the intersection region being anintersection of an unconstrained satellite positioning system errorspace based on the code phase measurement and an uncertainty region of alocation of the apparatus corresponding to the spatial information.

Clause 40. The storage medium of clause 39, wherein theprocessor-readable instructions to cause the processor to determine thesatellite positioning system carrier phase integer ambiguity searchspace comprise processor-readable instructions to cause the processor todetermine the satellite positioning system carrier phase integerambiguity search space based on a largest ellipse that fits within theintersection region.

Clause 41. An apparatus comprising:

a receiver;

a memory; and

a processor communicatively coupled to the receiver and the memory andconfigured to:

-   -   obtain a code phase measurement of a satellite vehicle signal        received via the receiver, the satellite vehicle signal        comprising a pseudorandom noise code and a carrier signal;    -   obtain spatial information corresponding to a wireless        terrestrial signal transferred between the apparatus and a        terrestrial base station; and    -   determine a satellite positioning system carrier phase integer        ambiguity search space based on the code phase measurement;

wherein the processor is configured to constrain a size of the satellitepositioning system carrier phase integer ambiguity search space based onthe spatial information.

Clause 42. The apparatus of clause 41, wherein the spatial informationcomprises a range uncertainty of a location of the apparatus relative tothe terrestrial base station.

Clause 43. The apparatus of clause 42, further comprising a transceiverthan includes the receiver, and wherein the processor is configured to:

transmit a first positioning reference signal to the terrestrial basestation;

measure a second positioning reference signal received from theterrestrial base station via the receiver; and

obtain a round trip time uncertainty corresponding to the firstpositioning reference signal and the second positioning reference signalas the range uncertainty.

Clause 44. The apparatus of clause 42 or clause 43, wherein the rangeuncertainty is less than two meters.

Clause 45. The apparatus of clause 42, wherein the spatial informationcomprises a plurality of range uncertainties of the apparatus relativeto a plurality of terrestrial base stations.

Clause 46. The apparatus of any of clauses 41-45, wherein the spatialinformation comprises an angular uncertainty of a location of theapparatus relative to the terrestrial base station.

Clause 47. The apparatus of clause 46, wherein the spatial informationcomprises a plurality of angular uncertainties of the location of theapparatus relative to a plurality of terrestrial base stations.

Clause 48. The apparatus of any one of clauses 41-47, wherein todetermine the satellite positioning system carrier phase integerambiguity search space the processor is configured to determine anintersection region, the intersection region being an intersection of anunconstrained satellite positioning system error space based on the codephase measurement and an uncertainty region of a location of theapparatus corresponding to the spatial information.

Clause 49. The apparatus of clause 48, wherein the processor isconfigured to determine the satellite positioning system carrier phaseinteger ambiguity search space based on a largest ellipse that fitswithin the intersection region.

Clause 50. A method of determining an integer ambiguity search space,the method comprising:

obtaining, at an apparatus, a code phase measurement of a satellitevehicle signal comprising a pseudorandom noise code and a carriersignal;

obtaining, at the apparatus, spatial information corresponding to awireless terrestrial signal transferred between the apparatus and aterrestrial base station;

determining, at the apparatus, a satellite positioning system carrierphase integer ambiguity search space based on the code phasemeasurement; and

constraining a size of the satellite positioning system carrier phaseinteger ambiguity search space based on the spatial information.

Clause 51. The method of clause 50, wherein the spatial informationcomprises a range uncertainty of a location of the apparatus relative tothe terrestrial base station.

Clause 52. The method of clause 51, further comprising:

transmitting a first positioning reference signal to the terrestrialbase station;

measuring a second positioning reference signal received from theterrestrial base station; and

obtaining a round trip time uncertainty corresponding to the firstpositioning reference signal and the second positioning reference signalas the range uncertainty.

Clause 53. The method of clause 51 or clause 52, wherein the rangeuncertainty is less than two meters.

Clause 54. The method of clause 51, wherein the spatial informationcomprises a plurality of range uncertainties of the apparatus relativeto a plurality of terrestrial base stations.

Clause 55. The method of any of clauses 50-54, wherein the spatialinformation comprises an angular uncertainty of a location of theapparatus relative to the terrestrial base station.

Clause 56. The method of clause 55, wherein the spatial informationcomprises a plurality of angular uncertainties of the location of theapparatus relative to a plurality of terrestrial base stations.

Clause 57. The method of any one of clauses 50-56, wherein determiningthe satellite positioning system carrier phase integer ambiguity searchspace comprises determining an intersection region, the intersectionregion being an intersection of an unconstrained satellite positioningsystem error space based on the code phase measurement and anuncertainty region of a location of the apparatus corresponding to thespatial information.

Clause 58. The method of clause 57, wherein determining the satellitepositioning system carrier phase integer ambiguity search spacecomprises determining the satellite positioning system carrier phaseinteger ambiguity search space based on a largest ellipse that fitswithin the intersection region.

Clause 59. An apparatus comprising:

means for obtaining a code phase measurement of a satellite vehiclesignal comprising a pseudorandom noise code and a carrier signal;

means for obtaining spatial information corresponding to a wirelessterrestrial signal transferred between the apparatus and a terrestrialbase station;

means for determining a satellite positioning system carrier phaseinteger ambiguity search space based on the code phase measurement; and

means for constraining a size of the satellite positioning systemcarrier phase integer ambiguity search space based on the spatialinformation.

Clause 60. The apparatus of clause 59, wherein the spatial informationcomprises a range uncertainty of a location of the apparatus relative tothe terrestrial base station.

Clause 61. The apparatus of clause 60, further comprising:

means for transmitting a first positioning reference signal to theterrestrial base station;

means for measuring a second positioning reference signal received fromthe terrestrial base station; and

means for obtaining a round trip time uncertainty corresponding to thefirst positioning reference signal and the second positioning referencesignal as the range uncertainty.

Clause 62. The apparatus of clause 60 or clause 61, wherein the rangeuncertainty is less than two meters.

Clause 63. The apparatus of clause 60, wherein the spatial informationcomprises a plurality of range uncertainties of the apparatus relativeto a plurality of terrestrial base stations.

Clause 64. The apparatus of any of clauses 59-63, wherein the spatialinformation comprises an angular uncertainty of a location of theapparatus relative to the terrestrial base station.

Clause 65. The apparatus of clause 64, wherein the spatial informationcomprises a plurality of angular uncertainties of the location of theapparatus relative to a plurality of terrestrial base stations.

Clause 66. The apparatus of any one of clauses 59-65, wherein the meansfor determining the satellite positioning system carrier phase integerambiguity search space comprise means for determining an intersectionregion, the intersection region being an intersection of anunconstrained satellite positioning system error space based on the codephase measurement and an uncertainty region of a location of theapparatus corresponding to the spatial information.

Clause 67. The apparatus of clause 66, wherein the means for determiningthe satellite positioning system carrier phase integer ambiguity searchspace comprise means for determining the satellite positioning systemcarrier phase integer ambiguity search space based on a largest ellipsethat fits within the intersection region.

Clause 68. A non-transitory, processor-readable storage mediumcomprising processor-readable instructions to cause a processor, of anapparatus, to:

obtain a code phase measurement of a satellite vehicle signal comprisinga pseudorandom noise code and a carrier signal;

obtain spatial information corresponding to a wireless terrestrialsignal transferred between the apparatus and a terrestrial base station;

determine a satellite positioning system carrier phase integer ambiguitysearch space based on the code phase measurement; and

constrain a size of the satellite positioning system carrier phaseinteger ambiguity search space based on the spatial information.

Clause 69. The storage medium of clause 68, wherein the spatialinformation comprises a range uncertainty of a location of the apparatusrelative to the terrestrial base station.

Clause 70. The storage medium of clause 69, further comprisingprocessor-readable instructions to cause the processor to:

transmit a first positioning reference signal to the terrestrial basestation;

measure a second positioning reference signal received from theterrestrial base station; and

obtain a round trip time uncertainty corresponding to the firstpositioning reference signal and the second positioning reference signalas the range uncertainty.

Clause 71. The storage medium of clause 69 or clause 70, wherein therange uncertainty is less than two meters.

Clause 72. The storage medium of clause 69, wherein the spatialinformation comprises a plurality of range uncertainties of theapparatus relative to a plurality of terrestrial base stations.

Clause 73. The storage medium of any of clauses 68-72, wherein thespatial information comprises an angular uncertainty of a location ofthe apparatus relative to the terrestrial base station.

Clause 74. The storage medium of clause 73, wherein the spatialinformation comprises a plurality of angular uncertainties of thelocation of the apparatus relative to a plurality of terrestrial basestations.

Clause 75. The storage medium of any of clauses 68-74, wherein theprocessor-readable instructions to cause the processor to determine thesatellite positioning system carrier phase integer ambiguity searchspace comprise processor-readable instructions to cause the processor todetermine an intersection region, the intersection region being anintersection of an unconstrained satellite positioning system errorspace based on the code phase measurement and an uncertainty region of alocation of the apparatus corresponding to the spatial information.

Clause 76. The storage medium of clause 75, wherein theprocessor-readable instructions to cause the processor to determine thesatellite positioning system carrier phase integer ambiguity searchspace comprise processor-readable instructions to cause the processor todetermine the satellite positioning system carrier phase integerambiguity search space based on a largest ellipse that fits within theintersection region.

OTHER CONSIDERATIONS

Other examples and implementations are within the scope of thedisclosure and appended claims. For example, due to the nature ofsoftware and computers, functions described above can be implementedusing software executed by a processor, hardware, firmware, hardwiring,or a combination of any of these. Features implementing functions mayalso be physically located at various positions, including beingdistributed such that portions of functions are implemented at differentphysical locations.

As used herein, the singular forms “a,” “an,” and “the” include theplural forms as well, unless the context clearly indicates otherwise.The terms “comprises,” “comprising,” “includes,” and/or “including,” asused herein, specify the presence of stated features, integers, steps,operations, elements, and/or components, but do not preclude thepresence or addition of one or more other features, integers, steps,operations, elements, components, and/or groups thereof.

As used herein, unless otherwise stated, a statement that a function oroperation is “based on” an item or condition means that the function oroperation is based on the stated item or condition and may be based onone or more items and/or conditions in addition to the stated item orcondition.

Also, as used herein, “or” as used in a list of items (possibly prefacedby “at least one of” or prefaced by “one or more of”) indicates adisjunctive list such that, for example, a list of “at least one of A,B, or C,” or a list of “one or more of A, B, or C” or a list of “A or Bor C” means A, or B, or C, or AB (A and B), or AC (A and C), or BC (Band C), or ABC (i.e., A and B and C), or combinations with more than onefeature (e.g., AA, AAB, ABBC, etc.). Thus, a recitation that an item,e.g., a processor, is configured to perform a function regarding atleast one of A or B, or a recitation that an item is configured toperform a function A or a function B, means that the item may beconfigured to perform the function regarding A, or may be configured toperform the function regarding B, or may be configured to perform thefunction regarding A and B. For example, a phrase of “a processorconfigured to measure at least one of A or B” or “a processor configuredto measure A or measure B” means that the processor may be configured tomeasure A (and may or may not be configured to measure B), or may beconfigured to measure B (and may or may not be configured to measure A),or may be configured to measure A and measure B (and may be configuredto select which, or both, of A and B to measure). Similarly, arecitation of a means for measuring at least one of A or B includesmeans for measuring A (which may or may not be able to measure B), ormeans for measuring B (and may or may not be configured to measure A),or means for measuring A and B (which may be able to select which, orboth, of A and B to measure). As another example, a recitation that anitem, e.g., a processor, is configured to at least one of performfunction X or perform function Y means that the item may be configuredto perform the function X, or may be configured to perform the functionY, or may be configured to perform the function X and to perform thefunction Y. For example, a phrase of “a processor configured to at leastone of measure X or measure Y” means that the processor may beconfigured to measure X (and may or may not be configured to measure Y),or may be configured to measure Y (and may or may not be configured tomeasure X), or may be configured to measure X and to measure Y (and maybe configured to select which, or both, of X and Y to measure).

Substantial variations may be made in accordance with specificrequirements. For example, customized hardware might also be used,and/or particular elements might be implemented in hardware, software(including portable software, such as applets, etc.) executed by aprocessor, or both. Further, connection to other computing devices suchas network input/output devices may be employed. Components, functionalor otherwise, shown in the figures and/or discussed herein as beingconnected or communicating with each other are communicatively coupledunless otherwise noted. That is, they may be directly or indirectlyconnected to enable communication between them.

The systems and devices discussed above are examples. Variousconfigurations may omit, substitute, or add various procedures orcomponents as appropriate. For instance, features described with respectto certain configurations may be combined in various otherconfigurations. Different aspects and elements of the configurations maybe combined in a similar manner. Also, technology evolves and, thus,many of the elements are examples and do not limit the scope of thedisclosure or claims.

A wireless communication system is one in which communications areconveyed wirelessly, i.e., by electromagnetic and/or acoustic wavespropagating through atmospheric space rather than through a wire orother physical connection. A wireless communication network may not haveall communications transmitted wirelessly, but is configured to have atleast some communications transmitted wirelessly. Further, the term“wireless communication device,” or similar term, does not require thatthe functionality of the device is exclusively, or evenly primarily, forcommunication, or that the device be a mobile device, but indicates thatthe device includes wireless communication capability (one-way ortwo-way), e.g., includes at least one radio (each radio being part of atransmitter, receiver, or transceiver) for wireless communication.

Specific details are given in the description to provide a thoroughunderstanding of example configurations (including implementations).However, configurations may be practiced without these specific details.For example, well-known circuits, processes, algorithms, structures, andtechniques have been shown without unnecessary detail in order to avoidobscuring the configurations. This description provides exampleconfigurations only, and does not limit the scope, applicability, orconfigurations of the claims. Rather, the preceding description of theconfigurations provides a description for implementing describedtechniques. Various changes may be made in the function and arrangementof elements.

The terms “processor-readable medium,” “machine-readable medium,” and“computer-readable medium,” as used herein, refer to any medium thatparticipates in providing data that causes a machine to operate in aspecific fashion. Using a computing platform, various processor-readablemedia might be involved in providing instructions/code to processor(s)for execution and/or might be used to store and/or carry suchinstructions/code (e.g., as signals). In many implementations, aprocessor-readable medium is a physical and/or tangible storage medium.Such a medium may take many forms, including but not limited to,non-volatile media and volatile media. Non-volatile media include, forexample, optical and/or magnetic disks. Volatile media include, withoutlimitation, dynamic memory.

Having described several example configurations, various modifications,alternative constructions, and equivalents may be used. For example, theabove elements may be components of a larger system, wherein other rulesmay take precedence over or otherwise modify the application of theinvention. Also, a number of operations may be undertaken before,during, or after the above elements are considered. Accordingly, theabove description does not bound the scope of the claims.

A statement that a value exceeds (or is more than or above) a firstthreshold value is equivalent to a statement that the value meets orexceeds a second threshold value that is slightly greater than the firstthreshold value, e.g., the second threshold value being one value higherthan the first threshold value in the resolution of a computing system.A statement that a value is less than (or is within or below) a firstthreshold value is equivalent to a statement that the value is less thanor equal to a second threshold value that is slightly lower than thefirst threshold value, e.g., the second threshold value being one valuelower than the first threshold value in the resolution of a computingsystem.

1. An apparatus comprising: a receiver; a memory; and a processorcommunicatively coupled to the receiver and the memory and configuredto: obtain a code phase measurement of a satellite vehicle signalreceived via the receiver, the satellite vehicle signal comprising apseudorandom noise code and a carrier signal; obtain spatial informationcorresponding to a wireless terrestrial signal transferred between theapparatus and a terrestrial base station; and determine a satellitepositioning system carrier phase integer ambiguity search space based onthe code phase measurement; wherein the processor is configured toconstrain a size of the satellite positioning system carrier phaseinteger ambiguity search space based on the spatial information.
 2. Theapparatus of claim 1, wherein the spatial information comprises a rangeuncertainty of a location of the apparatus relative to the terrestrialbase station.
 3. The apparatus of claim 2, further comprising atransceiver than includes the receiver, and wherein the processor isconfigured to: transmit a first positioning reference signal to theterrestrial base station; measure a second positioning reference signalreceived from the terrestrial base station via the receiver; and obtaina round trip time uncertainty corresponding to the first positioningreference signal and the second positioning reference signal as therange uncertainty.
 4. The apparatus of claim 2, wherein the rangeuncertainty is less than two meters.
 5. The apparatus of claim 2,wherein the spatial information comprises a plurality of rangeuncertainties of the apparatus relative to a plurality of terrestrialbase stations.
 6. The apparatus of claim 1, wherein the spatialinformation comprises an angular uncertainty of a location of theapparatus relative to the terrestrial base station.
 7. The apparatus ofclaim 6, wherein the spatial information comprises a plurality ofangular uncertainties of the location of the apparatus relative to aplurality of terrestrial base stations.
 8. The apparatus of claim 6,wherein the spatial information comprises a range uncertainty of thelocation of the apparatus relative to the terrestrial base station. 9.The apparatus of claim 1, wherein to determine the satellite positioningsystem carrier phase integer ambiguity search space the processor isconfigured to determine an intersection region, the intersection regionbeing an intersection of an unconstrained satellite positioning systemerror space based on the code phase measurement and an uncertaintyregion of a location of the apparatus corresponding to the spatialinformation.
 10. The apparatus of claim 9, wherein the processor isconfigured to determine the satellite positioning system carrier phaseinteger ambiguity search space based on a largest ellipse that fitswithin the intersection region.
 11. A method of determining an integerambiguity search space, the method comprising: obtaining, at anapparatus, a code phase measurement of a satellite vehicle signalcomprising a pseudorandom noise code and a carrier signal; obtaining, atthe apparatus, spatial information corresponding to a wirelessterrestrial signal transferred between the apparatus and a terrestrialbase station; determining, at the apparatus, a satellite positioningsystem carrier phase integer ambiguity search space based on the codephase measurement; and constraining a size of the satellite positioningsystem carrier phase integer ambiguity search space based on the spatialinformation.
 12. The method of claim 11, wherein the spatial informationcomprises a range uncertainty of a location of the apparatus relative tothe terrestrial base station.
 13. The method of claim 12, furthercomprising: transmitting a first positioning reference signal to theterrestrial base station; measuring a second positioning referencesignal received from the terrestrial base station; and obtaining a roundtrip time uncertainty corresponding to the first positioning referencesignal and the second positioning reference signal as the rangeuncertainty.
 14. The method of claim 12, wherein the range uncertaintyis less than two meters.
 15. The method of claim 12, wherein the spatialinformation comprises a plurality of range uncertainties of theapparatus relative to a plurality of terrestrial base stations.
 16. Themethod of claim 11, wherein the spatial information comprises an angularuncertainty of a location of the apparatus relative to the terrestrialbase station.
 17. The method of claim 16, wherein the spatialinformation comprises a plurality of angular uncertainties of thelocation of the apparatus relative to a plurality of terrestrial basestations.
 18. The method of claim 16, wherein the spatial informationcomprises a range uncertainty of the location of the apparatus relativeto the terrestrial base station.
 19. The method of claim 11, whereindetermining the satellite positioning system carrier phase integerambiguity search space comprises determining an intersection region, theintersection region being an intersection of an unconstrained satellitepositioning system error space based on the code phase measurement andan uncertainty region of a location of the apparatus corresponding tothe spatial information.
 20. The method of claim 19, wherein determiningthe satellite positioning system carrier phase integer ambiguity searchspace comprises determining the satellite positioning system carrierphase integer ambiguity search space based on a largest ellipse thatfits within the intersection region.
 21. An apparatus comprising: meansfor obtaining a code phase measurement of a satellite vehicle signalcomprising a pseudorandom noise code and a carrier signal; means forobtaining spatial information corresponding to a wireless terrestrialsignal transferred between the apparatus and a terrestrial base station;means for determining a satellite positioning system carrier phaseinteger ambiguity search space based on the code phase measurement; andmeans for constraining a size of the satellite positioning systemcarrier phase integer ambiguity search space based on the spatialinformation.
 22. The apparatus of claim 21, wherein the spatialinformation comprises a range uncertainty of a location of the apparatusrelative to the terrestrial base station.
 23. The apparatus of claim 22,further comprising: means for transmitting a first positioning referencesignal to the terrestrial base station; means for measuring a secondpositioning reference signal received from the terrestrial base station;and means for obtaining a round trip time uncertainty corresponding tothe first positioning reference signal and the second positioningreference signal as the range uncertainty.
 24. The apparatus of claim22, wherein the range uncertainty is less than two meters.
 25. Theapparatus of claim 21, wherein the spatial information comprises anangular uncertainty of a location of the apparatus relative to theterrestrial base station.
 26. The apparatus of claim 21, wherein themeans for determining the satellite positioning system carrier phaseinteger ambiguity search space comprise means for determining anintersection region, the intersection region being an intersection of anunconstrained satellite positioning system error space based on the codephase measurement and an uncertainty region of a location of theapparatus corresponding to the spatial information.
 27. Anon-transitory, processor-readable storage medium comprisingprocessor-readable instructions to cause a processor, of an apparatus,to: obtain a code phase measurement of a satellite vehicle signalcomprising a pseudorandom noise code and a carrier signal; obtainspatial information corresponding to a wireless terrestrial signaltransferred between the apparatus and a terrestrial base station;determine a satellite positioning system carrier phase integer ambiguitysearch space based on the code phase measurement; and constrain a sizeof the satellite positioning system carrier phase integer ambiguitysearch space based on the spatial information.
 28. The storage medium ofclaim 27, wherein the spatial information comprises a range uncertaintyof a location of the apparatus relative to the terrestrial base station.29. The storage medium of claim 27, wherein the spatial informationcomprises an angular uncertainty of a location of the apparatus relativeto the terrestrial base station.
 30. The storage medium of claim 27,wherein the processor-readable instructions to cause the processor todetermine the satellite positioning system carrier phase integerambiguity search space comprise processor-readable instructions to causethe processor to determine an intersection region, the intersectionregion being an intersection of an unconstrained satellite positioningsystem error space based on the code phase measurement and anuncertainty region of a location of the apparatus corresponding to thespatial information.